Question

The zoo keepers is worried because the number of visitors  __       smaller
and smaller.

A．become

B．became

C．is becoming

D．have become

Answer 1

C

考查主谓一致。the number of……的数目，谓语动词用单数形式。根据句意用现在进行时。句意：动物管理员担心游客的数量正在变得越来越少。