21. It will be a long time _______ he _______ back from Berlin.

　　A. when; will come

　　B. before; comes

　　C. after; is coming

　　D. since; comes

　　22.—Are you sure that you’ve met him before?

　　—______ I’m mistaken.

　　A. If

　　B. Since

　　C. Unless

　　D. More than

　　23. Does it matter _______ it rains tomorrow?

　　A. that

　　B. whether

　　C. if

　　D. as

　　24.—Do you remember _______ he came?

　　—Yes, I do. He came by car.

　　A. how

　　B. when

　　C. that

　　D. if

　　25. Be sure to write to us, _______?

　　A. will you

　　B. aren’t you

　　C. can you

　　D. mustn’t you

　　参考答案：

　　1～5 CDCAD

　　6～10 BCCBB

　　11～15 BBDDA

　　16～20DBBDA

　　21～25 BCCAA