Has Mr. Green travelled abroad yet—Not only Mr. and Mrs. Green but also their daughter abroad twice.

— I’m sure Andrew will win the first prize in the final. — I think so. He ______ for it for months. [ ]

Every possible means _______ to prevent the air pollution, but the sky is still not clear.[ ]

nk you for your help ______ foryour help, I wouldn’t have succeeded in my experiment

The careless driver knocked down the old man _________ was crossing the road.