My friend Bob just bought an apartment in a suburb of Beijing last week, which is much smaller than ours

but is three times _____ expensive. [ ]

A. very

B. so

C. too

D. as

传染性单核细胞增多症除由EB病毒引起外，其他较常见的病因是（）

A.支原体

B.衣原体

C.巨细胞病毒

D.腺病毒

E.风疹病毒