Difference between Should, Could, Would

Should is used to give advice and make recommendations and to talk about obligation, duty and what is expected to happen. Reference is to the present and the future. Should is similar to must but is not as strong as must:

• You should always wear a helmet when you go out cycling on busy roads.
  
  
• Once the pack is opened, the cooked meat inside should be consumed within three days.
  
  
• Should I tell her that her son is playing truant and skipping school? ~ I think you should. She should know about it.

------------Should and Should Have-------------
Should combines with the perfect infinitive to form should have + past participle when we want to talk about past events that did not happen, but should have happened. We are talking about an expectation and referring back to past time. Compare the following:
Before Tom leaves for work, his wife advises him:

• You should take your umbrella. It might rain. ~ No, I'll be all right. I shan't need it.
  
  But it did rain. When he arrives back home, his wife says:
  
  
• What did I tell you? You should have taken your umbrella. Then you wouldn't have got wet.
  
  Reference to the present and future:
  
  
• You should try and smoke less, Henry. Your health isn't very good and it's getting worse.
  
  Reference to the past:
  
  
• I should have given up smoking years ago, Mary. If I had, I wouldn't be in such bad shape now.

Would

If we want to talk about an unreal or unlikely situation that might arise now or in the future, we use a past tense in the if-clause and would + infinitive in the main clause. Compare the following and note that would is often abbreviated to 'd:

• How would you manage, if I wasn't here to help you? ~ I'd manage somehow. I wouldn't bother to cook. I'd go out to eat or bring home a take-away. I'd ask your mother to help me with the washing and the ironing. I know she'd help me.

-------------Would have-----------------
If we want to refer to the past and make a statement about things that did not happen, we need to use had + past participle in the if clause and would have constructions in the main clause. Note in these sentences that we can use 'd as the abbreviation for both had in the if-clause and would in the main clause:

• If he'd taken an umbrella, he wouldn't have got wet on the way home.
  
  
• If he'd taken his umbrella, he'd have stayed dry.

Could can be used to ask for permission, to make a request and express ability in the past. Compare the following:

• Could I borrow your black dress for the formal dinner tomorrow? ~ Of course you can!
  
  
• Could you do me a favour and pick Pete up from the station? ~ Of course I will!
  
  
• I could already swim by the time I was three. ~ Could you really? I couldn't swim until I was eight.

----------------Could Have--------------------
As with would have, and should have, could have is used to talk about the past and refers to things that people could have done in the past, but didn't attempt to do or succeed in doing:

• I could have gone to university, if I'd passed my exams.
  
  
• If he'd trained harder, I'm sure he could have completed the swim.

Note the difference between would have and could have in the following two examples. Would have indicates certainty that he would have won if he had tried harder, could have indicates that it is a possibility. Might have is similar in meaning to could have, although the possibility is perhaps not quite as great:

• If he'd tried a bit harder, he would have won the race.
  
• If he'd tried a bit harder, he could have won the race.
  
• If he'd tried a bit harder, he might have won the race.

Example:

Should have / Could have / Wouldn't have
Note the way in which all three of these modals are combined in these exchanges which refer to a meeting that has just taken place:

• Why did you come to the meeting? It didn't need both of us. You should have known that I would be there. ~ How could I have known you'd be there? I haven't spoken to you for a fortnight! ~ If I'd known you were intending to go, I certainly wouldn't have gone!
  

You will sometimes see would have written as would've, should have as should've and could have as could've.

All information is form http://www.bbc.co.uk/worldservice/learningenglish/grammar/learnit/learnitv195.shtml

Writing in English

People,

While surfing the web I found a web site with some tips to write in English.
I'm copying here all the material. If you are interested to know more about it, visit the web site.
http://www.dailywritingtips.com/

There you go:

50 Problem Words and Phrases

by Mark Nichol

Oh, what a tangled web we weave when first we practice to conceive written communication. So many pairs or trios of words and phrases stymie us with their resemblance to each other. Here’s a quick guide to alleviate (or is it ameliorate?) your suffering:
1. a while / awhile: “A while” is a noun phrase; awhile is an adverb.
2. all together / altogether: All together now — “We will refrain from using that two-word phrase to end sentences like this one altogether.”
3. amend / emend: To amend is to change; to emend is to correct.
4. amount / number: Amount refers to a mass (“The amount saved is considerable”); number refers to a quantity (“The number of dollars saved is considerable”).
5. between / among: The distinction is not whether you refer to two people or things or to three or more; it’s whether you refer to one thing and another or to a collective or undefined number — “Walk among the trees,” but “Walk between two trees.”
6. biannual / biennial: Biannual means twice a year; biennial means once every two years.
7. bring / take: If it’s coming toward you, it’s being brought. If it’s headed away from you, it’s being taken.
8. compare to / compare with: “Comparing to” implies similarity alone; “compare with” implies contrast as well.
9. compliment / complement: To compliment is to praise; to complement is to complete.
10. comprise, consist of / compose, constitute: Comprise means “include,” so test by replacement — “is included of” is nonsense, and so is “is comprised of.” The whole comprises the parts or consists of the parts, but the parts compose or constitute the whole.
11. connote / denote: To connote is to convey (“Air quotes connote skepticism or irony”); to denote is to specify (“A stop sign denotes the requirement to halt”).
12. continual / continuous: Continual events are frequently repeated, or intermittent. Continuous events are uninterrupted, or constant.
13. credible / credulous: To be credible is to be authoritative; to be credulous is to be gullible.
14. deserts / desserts: If you eat only cake, pie, ice cream, and the like, you eat just desserts. If you have it coming to you, you get your just deserts as well. (However, the connotation is negative, so hit the gym.)
15. different from / different than: The former phrase is preferred in formal writing; but “differently than” is always correct usage.
16. discreet / discrete: Discreet means “subtle”; discrete means “separate.” (“He discreetly reminded them of their discrete meanings.”)
17. each other / one another: “One another” is preferred in formal writing when more than two of something are being discussed.
18. economic / economical: Economic refers to the science of economics; economical suggests frugality.
19. elemental/elementary: What’s elemental is essential or integral to nature; what’s elementary is basic.
20. ensure / insure / assure: To ensure is to guarantee, to insure is to indemnify, and to assure is to comfort or convince.
21. epidemic / endemic / pandemic: An epidemic is the outbreak of disease in a limited place and time; an endemic disease is a recurring one peculiar to a place or population; a pandemic is pervasive over a wide geographical area.
22. forgo / forego: To forgo is to go without; to forego is to go before (and is generally used only in the forms foregoing and foregone, which are themselves rare).
23. gibe / jibe / jive: To gibe (soft g, as in gym) is to taunt or insult (though jibe is an alternate spelling), to jibe with is to coincide or fit, to jive is to deceive.
24. historic / historical: Something historic is remarkable for its impact on history; something historical is simply an event in history.
25. home in / hone in: To home in is to close in; to hone in is to confuse one word for another. (“Hone in” has no meaning.)
26. jealousy / envy: Jealousy is resentment; envy is covetousness.
27. lay / lie: Lay is transitive, associated with a direct object — “Lay that pencil down.” “Yesterday, I laid that pencil down.” “That pencil has been laid down.” Lie is intransitive, not so associated — “Lie down.” “Last night, I lay down.” “It was my plan to have lain down already.
28. leach / leech: To leach is to dissolve by percolation; to leech is to remove blood with a leech or to exhaust; as a noun, it means a parasitic worm or the human figurative equivalent, or the edge of a sail (also spelled leach).
29. libel / slander: Libel is written defamation; slander is the spoken equivalent.
30. may / might: May refers to factual or possible; might is appropriate for the hypothetical or counterfactual.
31. nauseous / nauseated: To be nauseous is to cause sickness. To be nauseated is to feel sick.
32. notable / noticeable / noteworthy: Something notable is worthy of note. Something noticeable is capable of being noticed. Noteworthy is a synonym of notable, though the former implies the unusual and the latter the commendable.
33. partly / partially: Partly means “in part”; partially means “incomplete” or, rarely, is an antonym for unfairly.
34. peak / pique: To peak is to reach the pinnacle; to pique is to arouse interest or to bother.
35. people / persons: People has assumed primacy; persons is reserved mostly as a synonym for bodies (“those belongings carried on their persons”).
36. persuade / convince: To persuade someone is to motivate them to do something; to convince someone is to lead them to understand or believe.
37. predominantly / predominately: Both forms are correct, but predominantly predominates.
38. purposely / purposefully: What’s done purposely is done on purpose; what’s done purposefully is done with a purpose.
39. regrettably / regretfully: Regrettably is a synonym for unfortunately; regretfully means just that — full of regret.
40. repetitive / repetitious: Both terms have acquired a negative connotation, but the former retains a more neutral meaning.
41. sensual / sensuous: Sensual has an erotic connotation; sensuous refers more neutrally to what is pleasurable to the senses.
42. since / because: Informally, these terms are interchangeable, but in formal writing, since should be used only to refer to time.
43. stationary / stationery: To be stationary is to stand still; stationery refers to letter-writing materials.
44. that / which: That is used restrictively (“The pencil that is sharp” — among more than one pencil, the one with that characteristic); which is employed nonrestrictively (“The pencil, which is sharp” — one pencil alone, possessing that characteristic). The distinction is rarely observed other than in American English.
45. tortuous / torturous: A tortuous experience is a winding one; a torturous one is painful.
46. transcript / transcription: A transcript is a thing; a transcription is the process of creating it.
47. verbal / oral: Verbal refers to both written and spoken communication, but oral is useful for distinguishing the latter from the former.
48. while / although / whereas: Informally, while is a synonym for the other two terms, but in formal writing it should be reserved for temporal connotations.
49. wreak / wreck: These terms do not share etymological origin; you wreck a party, but you do so by wreaking havoc.
50. whether / if: Both words are correct in expressing a choice, but the former is more appropriate in formal writing (“I can’t decide whether to go”), whereas the latter is better reserved for reference to possibility or probability (“I’ll go if you do”).

Study by yourself

Hey everyone,

I have some hints to give you.
If you want to improve your english by yourself, I´ll show you some possible ways.
Here we go:

For conversation in English and other languages
- www.livemocha.com
- www.babel.com

For conversation only in English
- www.englishcafe.com

A software to help you in English and any other language you wish to know
- www.rosettastone.com

How to understand the difference between the UK and Great Britain

How to understand the differences between British and American English

Modal Verbs of Obligation

Good tips guys!!!

Enjoy.
See you in class.
Leo

List of free dictionaries on-line

There are some web sites I usually use to learn english by myself.

They are real fun!

Enjoy

• http://www.thefreedictionary.com/ All in one
• http://dictionary.reference.com/ All in one
• http://www.ldoceonline.com/ The Longman Dictionary of Contemporary English Online
• http://www.howjsay.com/ A free online Talking Dictionary of English Pronunciation 
• http://wordia.com/ The authorative online textual dictionary. Bring words to life through video!