⑴Where are your parents?____                           A. Yes, I'd like some fruit.

⑵Is your brother sleeping in the room?____      B. They are at home. 

⑶Can I help you?____                                         C. She's playing the piano.

⑷Would you like some fruit?____                       D. No, I'm not.

⑸Can you see the red light?____                        E. She's singing.

⑹What is Helen doing?____                                F. Yes, please.

⑺Are you busy?____                                           G. No, I can't.

⑻What is she doing in the music room?____     H. No, he isn't.

告诉对方这个光盘是给迈克的，可以说：

若实数$a={\int }_1^e\frac{2}{x}dx$，则函数$f\left(x\right)=2\sin x+a\cos x$的图象的一条对称轴方程为(    )