By the time I got to the airport, the plane ________.
A. took off B. has taken off C. had taken off
The old man is ______ weak ______ say any words.
| A．too; to | B．so; that | C．very; that | D．so; to |
We should try our best _______ poor children _______ clean water and food.
| A．to provide; with | B．to provide; to |
| C．provide; to | D．provide; with |
You’d better go out for a walk instead of _______ in your bed.
| A．lying | B．lie | C．to lie | D．lay |
____________ is enough money to carry on with our work.
| A．We all need | B．All we need |
| C．We need all | D．We all need to |
It is really nice ___you ___ me work out the problem.
| A．of, to help | B．of, help |
| C．for, to help | D．for, help |