祈使句只能用and不能用then吗?为什么?

题目

祈使句只能用and不能用then吗?为什么?

答案

如果选项前边有个逗号,就用and;否则用then.
例如：Look around you at the wen and women whom you can call as happy as a king,______ you will see that they all have certain things in common.
A.but B.then C.and D.which
答案：C
Look around you at the wen and women whom you can call as happy as a king______ you will see that they all have certain things in common.
A.but B.then C.and D.which
答案：B