00-08-15

saladmimi

Cholesterol is present in large quantities in the nervous system, where ___ compound of myelin.

A. it a

B. a

C. being a

D. it is a

The choice is D, why?

Thank you.

liweimi1987

从句缺主语和谓语,还有定冠词,所以D

eml2005

从句引导词 前后是两个完整的句子，其中从句的主语谓语有时候可以省略！