_______ knowledge and experience are important to finish that task．（ ）
| A． |
Either |
B． |
Neither |
C． |
None |
D． |
Both |
I on the computer when Frank called me last night．（ ）
A．workB．will work
C．was workingD．am working
If you take this train， you in Shanghai in five hours．（ ）
A．arriveB．will arrive
C．arrivedD．have arrived
Zhaozhou Bridge is one of stone bridges in the world．（ ）
A．oldB．olderC．oldestD．the oldest
﹣ do you visit your grandparents，Tom？
﹣Twice a month．（ ）
A．How muchB．How oftenC．How longD．How soon
﹣ you give me a hand？ I can't move the box by myself．
﹣No problem．（ ）
A．CouldB．ShouldC．MustD．Need