—Peter，what are you doing？
—Oh，I_________a report about national heroes.（ ）
A．will writeB．am writing
C．wroteD．have written
I asked him a question， but he didn't reply．
Maybe he ________about something else while you were asking．（ ）
| A． |
thought |
| B． |
thinks |
| C． |
was thinking |
The song Dream It Possible often reminds me that we should always try our best and never ________catching our dreams．（ ）
| A． |
give up |
B． |
take up |
C． |
put up |
What should we pay attention to ________mistakes during the exams？
Some details．（ ）
| A． |
avoiding making |
| B． |
avoid to make |
| C． |
to avoid making |
The accident happened ________ a cold morning but luckily， no one was injured．（ ）
| A． |
at |
B． |
on |
C． |
in |
There are fifty students in this class， ________ of them are boys，so the number of the boys is 30．（ ）
| A． |
three fifth |
| B． |
three fifths |
| C． |
three five |