Some of the crops failed. ______, the cotton did pretty well.
A. [A] Then
Besides
C. Therefore
D. However
计算机病毒与正常程序的本质区别为( )。
A. 传染性
B. 破坏性
C. 潜伏性能
D. 衍生性
Nowhere else in the world ______ more beautiful sight than in Switzerland.
A. [A] you can find
B. is found
C. can you find
D. has been found
If it rains, we should not go out, but the sky ______perfectly clear.
A. [A] is
B. will be
C. was
D. had been