—I have tried very hard to find a solution to the problem, but in vain.

—Why not consult with Frank? You see, ________.[ ]

A. great minds think alike

B. two heads are better than one

C. a bird in the hand is worth two in the bush

D. it's better to think twice before doing something

可作液体制剂中防腐剂的是( )

A．PEG-400
B．山梨酸
C．HPMCP
D．泊洛沙姆
E．交联聚乙烯吡咯烷酮