_____ is known to all, paper was first made in China.
| A．It | B．That | C．Which | D．As |
A warning news report from Qatar announces that a group of Islam will continue to kill Americans wherever they are ________ they leave the Arab world forever.
| A．even though | B．in case | C．whenever | D．until |
— May I go and play football with Dick this afternoon, Dad?
— No, you can’t go out ________ your work is being done.
| A．before | B．until | C．as | D．after |
He waited ________ the volcano became quiet and he was able to return two days later.
| A．when | B．before | C．as | D．until |
She worked hard ________ everything would be ready by the time he came back.
| A．since | B．so that | C．as if | D．unless |
________ he studies hard, he will never pass the examination.
| A．If | B．Unless | C．Even if | D．Even though |