2 . A “Charity Wall”, ________spare clothes and books for people in need, recently appeared on a street in Beijing.

A．collecting

B．collected

C．collects

D．being collected

3 . Choosing a________ time to go to bed and then sticking with it is an instant way to have more deep sleep.

A．flexible

B．specific

C．precious

D．rough

4 . I was asked at the last minute to take part in the 1500m at my school’s sports day to ________the numbers. But amazingly I came out third.

A．take away

B．figure out

C．go over

D．make up

6 . Miss Lee helps me out when I have too much to do, and I will return the ________when I can.

A．obligation

B．formula

C．favour

D．opportunity

7 . The use of genetic engineering should be restricted to just those cases _____ the health of the mother or her baby is threatened.

A．in which ​​​

B．how

C．of whom

D．why

8 . He has been preparing for the conference since last week ________ he will deliver a speech on the reform of the company.

A．where

B．that

C．when

D．which