To our great surprise, we got _____ people to attend the conference as we expected.

A．twice as many

B．twice many

C．twice many as

D．as twice many

内源性感染病原微生物主要来源于

A．污染的血制品

B．病人自身正常菌群

C．病原携带者

D．其他病人

E．医护人员的手