The schoolbag be Tom's． Here， his name is on it．（ ）
| A． |
may |
B． |
could |
C． |
must |
D． |
might |
I went to your home yesterday morning， but you weren't in．
Well， I ______along the river at that time．（ ）
| A． |
walked |
B． |
was walking |
| C． |
am walking |
D． |
have walked |
To feed her little son． Mrs． Smith has to _______ the vegetables and meat．（ ）
| A． |
make up |
B． |
put up |
C． |
set up |
D． |
cut up |
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 |