I usually borrow books __________the library.
[ ]
A. from
B. in
C. to
D. at
答案:A
孕初期为减少恶心、食欲不振现象,应增加何种维生素供给()
A.VB1
B.VB2
C.VB6
D.VC
E.VB12
用于pH值测定的草酸三氢钾标准缓冲液在25℃时的pH为()
A.4.50
B.6.86
C.9.18
D.7.41
E.1.68