1.Jim has changed a lot since he entered college.He is not the man ____ he used to be. A.what B.which C.as D./
热心网友
D.因为he used to be是定语从句，修饰the man，用who/that连接，用that时可省略。
热心网友
B
热心网友
应为：C
热心网友
d
热心网友
A正确。因为he used to be____后边缺少做表语的成分，所以只有what 可以充当，所以选项A正确。