—The air pollution is terrible．
—It will be worse________we take action to protect the environment．
| A．if |
| B．unless |
| C．until |
| D．when |
The dictionary belong to Sam．You can see his name on it．（ ）
| A． |
can |
B． |
must |
C． |
need |
D． |
would |
Nelson exercises because he has too much work every day．（ ）
| A． |
usually |
B． |
always |
C． |
often |
D． |
seldom |
Humans can not make progress dreams．（ ）
| A． |
with |
B． |
without |
C． |
through |
D． |
about |
The cover of the book comfortable．It's made of silk．（ ）
| A． |
tastes |
B． |
feels |
C． |
looks |
D． |
sounds |
His grandfather did his best to keep the tree ，but it died in the end．（ ）
| A． |
alive |
B． |
asleep |
C． |
absent |
D． |
awake |