Most of us still wonder ___________ it is ________ makes those honest peasant workers, without being paid at all, resign themselves to the bosses.

_______ all these people have in common is ________ they have succeeded.

I don’t think  I’ ll  be able  to go mountain climbing  tomorrow________?

He made another wonderful discovery, ______ of great importance to science.

（2006年普通高等学校招生全国统一考试湖南卷，26）As the busiest woman in Norton,she made_________her duty to look after all the other people’s affairs in that town.