I like reading in the city library ________ I often lose myself in a world of good books on weekends.

A．which

B．that

C．/

D．where

口腔黏膜的叙述不正确的是( )

A．咀嚼黏膜的上皮较厚，表层有角化

B．腭黏膜由两部分组成，前1/3为硬腭，后2/3为软腭

C．被覆黏膜表层无角化

D．舌背黏膜属于特殊黏膜

E．硬腭为咀嚼黏膜