It was for us to solve the math problem， few of us could even understand it．（ ）
| A． |
easy enough |
B． |
enough easy |
| C． |
difficult enough |
D． |
enough difficult |
When I want to go out to play with my friends， my mother always says，"_____ at home．Don't waste your time．"（ ）
| A． |
Stay |
B． |
Stays |
C． |
To stay |
D． |
Staying. |
As the most exciting and traditional way to shop， street markets _____ here and there in China these days．（ ）
| A． |
find |
B． |
found |
C． |
are found |
D． |
were found |
Let's go camping if it _____ next Saturday．
But nobody knows if it_____．（ ）
| A． |
is fine； rains |
| B． |
will be fine； rains |
| C． |
is fine； will rain |
| D． |
will be fine； will rain |
All the volunteers were very tired， but _____ of them had a rest．
They were busy helping the firemen．（ ）
| A． |
both |
B． |
neither |
C． |
all |
D． |
none |
Putting out forest fire is regarded as one of _____ problems in the world．（ ）
| A． |
difficult |
B． |
more difficult |
| C． |
most difficult |
D． |
the most difficult |