Tenses

[rajeshmalladi]

Could anyone please explain me the rules for using different possible combinations of tenses in a sentence.

Eg: Can we use present perfect and past perfect in one sentence, past perfect and past progressive in one sentence, etc.

I have a TOEFL book which says the various tenses that could appear in a dependent clause if the main clause is either in present tense or in past tense only.
But it doesn't say anything about the main clause containing other tenses except the present and past(eg:present perfect). Please explain.
Thank you,
Rajesh

[Pete]

Sorry, but I still haven't found a list. We do much better with specific questions, including examples, than with questions that are very general. Sometimes a definite rule of grammar comes to mind to answer a general question, or maybe we can find a discussion on the Web, but when that isn't the case, we really aren't linguists and don't have the tools to make up rules or lists that we are sure cover all cases. Sorry.

(Of course, it is ok to ask, but don't be surprised when sometimes the answer is less than satisfying.)