We'd better ________when he is thinking，as he prefers to solve problems on his own．（ ）
| A． |
let him down |
B． |
cheer him up |
| C． |
leave him alone |
D． |
ring him up |
In the library， students are required to keep ___________ and move ____________．（ ）
A．quiet； quietB．quiet； quietly
C．quietly； quietD．quietly； quietly
I won't stop loving English ___________ the sun rises in the west．（ ）
A．ifB．althoughC．becauseD．unless
He chose to study in a junior school near his home． It __________ to be a wise decision．（ ）
A．put outB．put onC．turned outD．turned on
You must raise your hand if you have any questions in class．_________， your teacher won't notice you．（ ）
A．OtherwiseB．AnyhowC．InsteadD．Moreover
______________I keep the book for a week？
Sorry， I'm afraid you ______________．（ ）
A．Need； couldn'tB．Need； can't
C．May； couldn'tD．May； can't