Alex has finally bee an astronaut, all his family members think is his dream career.
A. which
B. who
C. that
D. whom
网友回答
(答案→)A. which
B. who
C. that
D. whom
解析： 句意：Alex最后终于成为一名宇航员，所有的家庭成员都认为这是他梦想的事业。这里使用了非限制性定语从句，用which指代上文的内容，在定语从句中which做主语，that不能引导非限制性定语从句，所以选A。