Tony has ______ healthy food. [ ]
A. a lot
B. lot of
C. many
D. a lot of
答案:D
可用作注射用包合材料的是()
A.β-环糊精
B.α-环糊精
C.γ-环糊精
D.羟丙基-β-环糊精
E.乙基化-β-环糊精
变压器送电时,尤其是大容量变压器,应在听到空载运行的声响3min后,才能进行下一步操作。