下列关于劳逸损伤与疾病发生关系的叙述，错误的是（）。

A.久视伤血

B.久坐伤肉

C.久立伤骨

D.久卧伤神

E.久行伤筋

Nothing is so easy as ________ parents to raise their expectations of their children too high.

A．of

B．to

C．by

D．for