【原创】The workers in the Huashan Mountain have to _______ rubbish to keep the mountains clean.
| A．turn up | B．pick up | C．mix up | D．give up |
In Britain, you must reach 18 ________ you want to drive a car.
| A．because | B．though | C．if | D．so |
I'll write a letter to you ________ I arrive in New York.
| A．as soon as | B．until | C．since | D．for |
I told him the news ________he came back yesterday.
| A．until | B．as soon as | C．unless | D．as |
—Ring me up ________ you come to my house, will you?
—Sure, I will.
| A．though | B．while | C．before | D．until |
You will fail the exam ________ you work hard.
| A．unless | B．once | C．since | D．after |