________is power is a famous saying known to all.
| A．What knowledge | B．How knowledge |
| C．That knowledge | D．When knowledge |
It was when I arrived home _____ I realized I had left my bag in the library.
| A．what | B．because | C．that | D．until |
You can complain, but I doubt _____ it’ll make any difference．
| A．if | B．what | C．that | D．how |
I won’t be able to answer any phone all the afternoon．I_____________ a conference．
| A．am attend | B．was attending |
| C．will be attending | D．will have attended |
The old couple have been married for 40 years and never once ___________ with each other．
| A．they had quarreled | B．they have quarreled |
| C．have they quarreled | D．had they quarreled |
This problem is far _____ me．I can’t work it out on my own．
| A．over | B．above | C．from | D．beyond |