The Biology problem is too hard，so students can work it out．（ ）
| A． |
little |
B． |
few |
C． |
a little |
D． |
a few |
The safety of food has become one of the ________ problems in our daily life．（ ）
A．importantB．more important
C．most important
In order to make our city more beautiful，we have planted _______ trees these years in Yiyang．（ ）
A．three thousandsB．thousand of
C．thousands of
Are these _________ new trousers？
No，they are not _________．（ ）
A．your，myB．your，mineC．yours，mine
________ fine weather it is today!（ ）
A．WhatB．HowC．What a
It took me half _______ hour to finish my homework last night．（ ）
A．aB．anC．the