It is not always easy for the public to see _______ benefit a new invention can be of to human life.
| A．whose | B．what | C．which | D．that |
A number of foreign guests were invited to the party, but 20 of them didn’t___________.
| A．turn up | B．break up | C．look up | D．make up |
I think you should complain —______,of course, you are happy with the way things are.
| A．if | B．unless | C．as | D．because |
－How do you usually find out about new software?
－In the magazines like Popular Electronics. That’s______computer companies usually advertise.
| A．which | B．where | C．what | D．why |
______the address, Tom sent the email to his teacher.
| A．Having checked | B．Checked | C．Being checked | D．To check |
They all wanted to stop working because they were tired, but______of them would say sl.
| A．any | B．some | C．none | D．neither |