我想问一下关与to 着词在句子里面的用法

我想问一下关与to 着词在句子里面的用法
这是一个选择题/
the doctor refused to_____about hie operation.
1.say him 2.tell to him 3.speak him 4.speak to him.
在这里我觉得应该该是 2.tell to him
还有一个问题.
when will he be allowed to go home?when will they______?
1.let him go 2.let him to go 3.leave him to go 4.leave him.
在这里我觉得是1.let him go不用to 这样是对的吗?
第三个问题是
he will have to stay in hospital .that's what he_______
1.has done 2.must do 3.must be doing 4.have must done
在这里我选择的是3.must be doing