(2013·浙江温州二模)Scientists have found evidence global warming caused the world's first horses to bee smaller nearly 50 million years ago.
A. what
B. that
C. which
D. whether
网友回答
A. what
(答案→)B. that
C. which
D. whether
解析：选B 考查同位语从句。句意：科学家们已经找到证据，证明大约5 000万年前，全球变暖使世界上首批马的个头变小了。根据句意可知，空后说的是evidence的内容，并且引导词在从句中不作成分，所以用that引导同位语从句。