Re: if so
Yoong Liat wrote:I could eat three plates in five minutes!
Would it be wrong if 'can' is used instead of 'could'? If so, what if the difference?
It would not be wrong at all. It depends on what you are trying to say. As as always, Yoong Liat, (!) context is crucial, as the following examples (hopefully) will illustrate:
"I can (present tense) eat three in plates five minutes!" might mean "I am capable of eating three plates at any time..." or it might mean "I am able and willing to eat three plates right now..."
"I could (past tense) eat three plates in five minutes!" might mean "I was once able to eat three plates in five minutes" [Implication: I can't now]
"I could (conditional) eat three plates in five minutes!" might mean "I would be able to eat three plates etc [e.g. if I were called upon to do so/if I wanted to].
"I could (conditional) eat three plates in five minutes!" might mean "I am so hungry I am ready to eat three plates etc . (Common UK English saying: "I am so hungry I could eat a horse!"
Quote:Does "if so" mean "If it is possible"?
It means "if it is true" or "if it is the case".