There was so much noise outside that the teacher couldn't make herself____（ ）
| A． |
hear |
B． |
heard |
C． |
hearing |
D． |
to hear |
As far as I know， the robot that can sweep the floor ________ in the 1980s．（ ）
| A． |
is invented |
B． |
invented |
| C． |
was invented |
D． |
has invented |
The man _______ be a doctor in this hospital， but I'm not sure．（ ）
| A． |
must |
B． |
would |
C． |
can |
D． |
might |
Ling ling， you'll feel sleepy tomorrow _______ you go to bed early．
OK， Mom． I'll go to bed at once．（ ）
| A． |
if |
B． |
unless |
C． |
though |
D． |
because |
Frank is an honest boy and he never tells a lie． We all _______ him．（ ）
| A． |
miss |
B． |
mind |
C． |
doubt |
D． |
trust |
Mr．Liu _________ watches TV．He thinks watching TV is a waste of time．（ ）
| A． |
often |
B． |
seldom |
C． |
always |
D． |
usually |