婴儿的吮吸功能异常，下颌被降颌肌群向后下牵引，可发展成为（）

A.下凳颌后缩畸形

B.佝偻病

C.维生素A缺乏

D.吮指习惯

E.舌习惯

In order to support the big family, he worked so hard that___________ he made himself ill.

A．occasionally

B．purposefully

C．normally

D．eventually