21．It was not until dark ____ he found ____ he thought was the correct way to slove the problem.
| A．when; what | B．that; that | C．that; what | D．when; that |
______by many people，the spokesman made an exciting speech．
| A．Surrounding | B．Having surrounded | C．Surrounded | D．Surround |
At the same time，they are taking strong _______ to protect wildlife resources．
| A．actions | B．measures | C．step | D．efforts |
To enjoy the scenery，he would rather _____ long hours on the train ___ travel by air．
| A．spend ; to | B．to spend; rather than | C．spend ; than | D．spending; while |
His suggestion ____ the meeting be delayed was turned down.
| A．which | B．that | C．/ | D．it |
-— How far apart do they live?
---- _______ I know，they live in the same neighbourhood．
| A．As long as | B．As well as | C．As far as | D．As often as |