—How long have you ________ there?
—About four years.[ ]
A. come
B. gone
C. left
D. worked
答案:D
GB/T5750.4中测定水的总硬度的乙二胺四乙酸二钠标准溶液浓度是()。
A.0.1mol/L
B.0.01mol/L
C.0.02mo1/L
D.0.05mol/L
感觉障碍包括哪些