单选题：____ most of the earth's surface is covered by water, fresh..

_____ you have come here, you may devote yourself to doing your work.A. As ifB. Even if C. In case D. Now that

You'd better take an umbrella with you _____ it rains.A. for B. because C. in case D. since

Why not stay at home _____the road is so slippery after the heavy snow?A. when B. unless C. even ifD. now that

She insisted that she ______ not guilty , but we insisted that she ____ into prison. [ ]A．was; be put B．be ; was put C．should be; was put D．was;should put

_____he has made up his mind, no one can make him change it.A. Once B. Until C. Unless D. As