Question

They kept trying _____ they must have known it was hopeless.

A．if	B．because
C．when	D．where

Answer 1

C

考查连词。if 如果，是否；because因为；when既然，当……时；where在哪儿。句意：考虑到他们一定知道这是没有希望的，他们坚持继续尝试。选C。