—Is this your baseball, David? —No, it's not . It's Helen's.
| A．his | B．yours | C．mine | D．hers |
I was about to enter the office ______ I heard someone cry “ Earthquake!” loudly outside.
| A．while | B．when | C．before | D．after |
I am considering buying ______ used car for its lower price.
| A．an | B．a | C．the | D．/ |
It is clever ________ you ________ me work out the maths problem.
| A．of; to help | B．of; help |
| C．for; to help | D．for; help |
There is ________ in the classroom, so we can see ________.
| A．enough light; clearly enough |
| B．light enough; clearly enough |
| C．enough light; enough clearly |
| D．light enough; enough clearly |
We should prevent the children ________ the bad programmes.
| A．to watch | B．from watching |
| C．from watch | D．to watching |