—I am trying touse the machine, but it won’t start. —Let me show youhow to start it. See all you hav

—I am trying touse the machine, but it won’t start.

—Let me show youhow to start it. See all you have to do is ________ this button.

A.to press

B.press

C.to turn

D.turn

答案及解析： A

解析：

不定式作表语，表示将来的动作。