Most villagers agree that horses are far more pleasant _______ than tractors, but they are less efficient.

A．looking at

B．to look at

C．to be looked at

D．being looked at

不符合视力下降而眼底正常的眼病有（）

A.球后视神经炎

B.玻璃体出血

C.癔病

D.视锥细胞变性

E.弱视