What ______ had Bob walked farther, as far as the river bank?
| A．would happen | B．could happen | C．would have happened | D．needn’t have happened |
They did not stop fighting_____ there was no enemy left.
| A．until | B．after | C．when | D．since |
I was about to leave my house _____the phone rang.
| A．while | B．when | C．as | D．after |
_____ we were singing, the teacher came in.
| A．Before | B．after | C．As | D．Until |
You like sports_____I’d like to read.
| A．when | B．while | C．but | D．yet |
The hard he works, _____he will make.
| A．the greater | B．the greater progress |
| C．and the more | D．more |