Most environmental problems exist because adequate measures for preventing them___taken in the past.A.was not B.were not
问题描述:
Most environmental problems exist because adequate measures for preventing them___taken in the past.A.was not B.were not C.were not being D.being not 请说明原因,
答
B.were not
Most environmental problems(主语) exist(谓语) because(引导原因状语从句) adequate measures(从句的主语) for preventing them (主语的定语)were not taken(被动语态做谓语) in the past