— I think students should have mobile phones to call their parents.

—_____. They often use them to play games instead.

A．I hope so

B．I don't agree

C．No problem

D．Good idea

青少年患者常见的骨肿瘤有（）.

A.骨软骨瘤

B.骨肉瘤

C.软骨肉瘤

D.转移癌

E.脊索瘤