以病原治疗为主的传染病是（）

A.乙型脑炎

B.肾综合征出血热

C.霍乱

D.恙虫病

E.水痘

Friendship helps us understand （） we are, （） we need each other and （） we can do for each other.

A. what when that

B. who why what

C. where why that

D. who when how much