Cold ______ the night air was, he slept soundly because he was so tired after working for a whole day.
| A．although | B．while | C．however | D．as |
He hasn't decided __ to London.
| A．whether to sail or fly | B．if to sail or fly | C．whether sailing or flying | D．if sailing or flying |
In many ways, riding on a bike is simliar to ___.
| A．driving a car | B．when you drive a car | C．drive a car | D．when driving a car |
We did the job as fast as we could, ___ to finish it earlier.
| A．hoping | B．to hope | C．hoped | D．being hoped |
We had better not __ them busy all day long.
| A．to keep | B．keeping | C．kept | D．keep |
The girl is dangerous ___.
| A．to make friends | B．make friends with | C．to make friend with | D．to make friends with |