We always keep ____ spare paper, in case we run out.  [ ]

A. too much

B. a number of

C. plenty of

D. a good many

* * 内有大量泡沫样白带最常见于

A．慢性宫颈炎

B．滴虫性 * * 炎

C．老年性 * * 炎

D．念珠菌性 * * 炎

E．慢性盆腔炎