The textbooks ________ for teaching English as a foreign language came out in the 16th century.
| A．having written | B．to be written |
| C．being written | D．Written |
He said that he would write to us but so far we ___________ from him.
| A．didn’t hear | B．haven’t heard | C．shouldn’t have heard | D．hadn’t heard |
__________ good exercise.
| A．Climbing hills is | B．Climbing the hill is |
| C．The climbing hills are | D．The climbing of hills are |
I don’t know who invented __________ telescope, but I think it is __________ most
useful invention.
| A．the, the | B．the, a | C．a, the | D．a, a |
Rarely _____________________ .
| A．the temperature falls below zero here | B．falls the temperature below zero here |
| C．does the temperature fall below zero here | D．has the temperature fallen below zero here |
This is the only way we can imagine _______ the overuse of water in the students’ bathrooms.
| A．reducing | B．reduced | C．reduce | D．to reduce |