We ________ see which way to go if the stars do not twinkle（闪耀）so.（ ）
| A． |
can not |
B． |
should not |
C． |
must not |
D． |
need not |
Blue whales are ． We should try to protect them．（ ）
A．in timeB．in publicC．in danger
﹣ does Liu Chuanjian do？
﹣He's a pilot of Sichuan Airlines． He's a hero!（ ）
A．WhatB．WhereC．When
﹣I tried many ways to solve the problem， but of them worked．
﹣Never give up． You' ll surely make it．（ ）
A．allB．noneC．neither
Tony is the best student in the class because he works than the others．（ ）
A．hardB．harderC．hardest
﹣Must I hand in the survey on the use of bicycle﹣sharing right now？
﹣No， you ．（ ）
A．needn'tB．can'tC．shouldn't