Man-made-satellites______ into space by many countries.
| A．was sent up | B．is sent up | C．have been sent up | D．has been sent up |
Mark needs to learn Chinese _______ his company is opening a branch in Beijing.
| A．unless | B．until | C．although | D．since |
sales of cars up by 30% last year, the traffic in Beijing has become increasingly terrible.
| A．With | B．Since | C．For | D．As |
It is recognized that the part ___ the UN plays in international relations is important.
| A．in which | B．where | C．that | D．of which |
Who would you rather ______ with the teacher about the problem?
| A．talking | B．talk | C．have talked | D．have talk |
When _____ the letter, tears came to her eyes.
| A．she was reading | B．reading | C．she reading | D．read |