you make sure -----------?

you make sure ___________?
Can you make sure ___________?
A.that he will come here today B.when he will come here today
C.will he come here today D.whether will he come here today
A和B的区别 B中when是作主语的吗
I don’t know ___________.
A.the reason why can be B.why the reason may be
C.what the reason can be D.what the reason may be
这题看不懂 这里面can be和may be是可能的意思吗?
参考答案是A C
不是A D