用石墨作电极电解2 mol·L-1NaCl和1 mol·L-1MgSO4混合溶液时,下列曲线合理的是
[ ]
A.
B.
C.
D.
答案:D
造成矿井充水的水源有哪几种类型?
I don't know the park, but it's()to be quite beautiful.
A.said
B.told
C.spoken
D.talked