—Shall I help you with the math problem?—________.
Carol said the work would be done by October, _____personally I doubt very much.
He was hiding behind the door _________ he could see what was happening. A. whichB. from whereC from which D. where
Recently I bought an ancient Chinese vase, _____ was very reasonable.
_____ has already been pointed out, grammar is not a set of dead rules.
He lived in London for 3 months, during ____ time he learned some English.