SI: Has the main engine been warmed up? S2: No. It hasn't. Q:

SI: Has the main engine been warmed up? S2: No. It hasn't. Q: Which of the following is true?

A.The main engine has been warmed up

B.The main engine has not been warmed up.

C.The main engine cannot be warmed up

D.The main engine needn't to be warmed up.

正确答案是B