This year President Xi Jinping wrote a letter to the young pioneers China to celebrate ________ 70th anniversary（周年纪念日）． （ ）
A．theirB．themC．theirsD．they
﹣Whose notebook is this？
﹣It ___ be Alan's．It looks like his．（ ）
| A． |
must |
B． |
can't |
C． |
might |
D． |
mustn't |
Fewer people smoke now﹣．The number of smokers is（ ）
| A． |
falling |
B． |
rising |
C． |
growing |
D． |
increasing |
It's going to rain．We'll be wet ___we get home．（ ）
| A． |
if |
B． |
after |
C． |
when |
D． |
unless |
﹣I'm looking forward to the picnic tomorrow．
﹣I'm sorry to tell you that we have _____the picnic till next weekend．（ ）
| A． |
gone on |
B． |
put off |
| C． |
given up |
D． |
prepared for |
I can't find my bag．Maybe someone took it _______．（ ）
| A． |
in fact |
B． |
by mistake |
| C． |
by accident |
D． |
in person |