On our arrival, we found Tom _____at the desk and ______a letter.
| A．seated, wrote | B．sitting, written | C．seating, writing | D．seated, writing |
—Where did ________traffic accident happen,sir?
—It took place at ________crossroads by the bank.
| A．a;/ | B．the;a | C．/;a | D．a;a |
__________ the text a second time，the meaning will become clearer to you.
| A．Read | B．Reading | C．If reading | D．When you read |
Information technology is taught in most schools，__________we have entered the information society.
| A．so | B．while | C．still | D．for |
Scientists say it may be five or six years __________it is possible to test this medicine on human patients.
| A．since | B．after | C．before | D．when |
Parents should take seriously their children’s requests for sunglasses __________.
| A．because | B．though | C．unless | D．if |