The engineers made two big plans for the dam, ____ was never put in force.
| A．one of them | B．which | C．one of which | D．every one of which |
The time she has devoted in the past decade ______ the disabled is now considered to be very valuable.
| A．helping | B．to help |
| C．to helping | D．for helping |
—Do you still remember the days ______ we spent in the countryside ten years ago?
—Yes，I'll never forget the experience.
| A．that | B．when | C．on which | D．what |
All the universities have duty to ______ their students ______ of the quick development of the scientific world.
| A．make；known | B．have；understood |
| C．keep；informed | D．find；involved |
I don’t think the experiment is ______ failure. At least we have gained _______ experience.
| A．the; the | B．a; the |
| C．a; 不填 | D．a; a |
— I’m bored. Let’s go to the cinema.
— ______. I’m really busy at the moment.
| A．My treat | B．Forget it |
| C．It depends | D．It’s a deal |