单选题 He pointed out that a (considerable) gap (existing) between the number of hours people (are paid) for working and the number of hours (spent) in productive labor.

A、 considerable
B、 existing
C、 are paid
D、 spent

【正确答案】 B

【答案解析】将existing改为exists，否则，该句就会没有谓语动词了。该句中people are paid for working是定语从句，修饰其前面的the number of hours。gap裂口，缺口；差异，隔阂。