good manners to say “Sorry when you knock into someone but no need to say it aga

      good manners to say “Sorry” when you knock into someone but    no need to say it again and again .

A.There are ; there is

B.It is ; there is

C.There is ; it is

D.It is ; it is

试题答案

B

第一空it为形式主语，it代指的是真正的主语to say sorry when you knock into someone,形式主语只能选择it，第二空是固定句型，there is no need to do sth 意为，没有必要干某事