question

[Atult718]

I was reading the Manhattan GMAT sentence correction book. On page 48 If...then clause is mentioned. It says that WOULD AND COULD never appear in the IF clause.

So my question is.... When we say... "If I could do it, then I would do it".... This everyday sentence must be wrong then right?

If it is wrong then what is the correct sentence? Or that sentence is an exception to the rule?. If this is an exception then which other sentences can be put into that exception group.

[isisalaska]

I guess it must be wrong, such as many other expressions used in colloquial English.

With "if" you need the subjective, remember this popular tune:
"if I were a rich man..."

Maybe this one would be better

“If I were able to do it I would do SO”