many species of animals which once lived on the earth( ) no longer in existence.A.is B.are C.was D.were
问题描述：
many species of animals which once lived on the earth( ) no longer in existence.
A.is B.are C.was D.were
答
首先看到many species就可排除A和C 接着是看时态，这句话意思为：许多在地球上生活的动物物种已不存在了。从这句话可以看出到目前为止许多物种已经灭绝了，物种的灭绝在现在这个时态以前，所以用过去时。选择 D. were
答
B。指曾经居住在地球上的许多种动物不存在了。 所以用are
答
many species of animals which once lived on the earth are no longer in existence species,单数和复数形式相同 例句：1 Most species provide good forage.（主语书复数 用are）2 This species provides good fo...
答
B are 系表结构，主语是species，单复数同。
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