Tom always prefers _________ rather than _______ a bike.
| A．walk; ride | B．walk; riding | C．to walk; ride | D．riding; to ride |
The reason why she couldn’t come to the meeting was_____ she had not been invited.
| A．because | B．which | C．that | D．why |
____ surprised me most was ______ they had finished it so quickly.
| A．What, what | B．That, that | C．What, that | D．That, what |
Maria has to baby-sit. That’s______ she can't come with us.
| A．why | B．ho | C．when | D．what |
--- I rang you at about ten, but there was no reply.
--- Oh, that was probably ____ I was seeing the doctor.
| A．when | B．why | C．what | D．that |
15. _______ all the inventions have in common is _____they have succeeded.
A. What; what B. That; that C. What; that D That; what