1 . It’s clever to know what ________ us to have stress.

A．makes

B．leads

C．conducts

D．causes

2 . 科学家就人们的睡眠质量进行了很多调查。
Scientists ________ people’s sleeping quality.

3 . Ken’s mother was a ________ ten years ago. (conduct)

4 . The visitors were ________ over the factory. (conductor)

5 . We have to _______ a product test before selling the computers.

A．condition

B．construction

C．comfort

D．conduct

6 . By c________ several investigations, the police have successfully found out the murderer of the crime.

7 . I’m going to ___________ one more school outing next Tuesday.

A．conduct

B．organize

C．make

D．planned

8 . If you can not understand the chemistry in words, you can c________ an experiment.