The chairman thought _____ necessary to invite Professor Smith to speak at the meeting.

A．that

B．it

C．this

D．him

多以60%乙醇，采用渗漉法、浸渍法或回流法制备。制成品可以替代药酒服用

A．水溶性颗粒剂
B．酒溶性颗粒剂
C．混悬性颗粒剂
D．块状冲剂
E．泡腾性颗粒剂