--- Listen! Someone is playing the piano.

--- Wow! __________ beautiful music! I like it very much.

A．What

B．How a

C．What a

D．How

眼球壁的结构由外向内依次为（）。

A.角膜、巩膜和脉络膜

B.角膜、巩膜和视网膜

C.虹膜、脉络膜和视网膜

D.纤维膜、虹膜和视网膜

E.纤维膜、血管膜和视网膜