既能活血，又能凉血的药是
A．川芎、丹参B．五灵脂、血竭C．丹参、郁金D．血竭、穿山甲
参考答案：C
磁铁矿、赤铁矿、褐铁矿、菱铁矿及黄铁矿，其分子式分别是什么？
As the temperature for a given mass of air increase, the（）.
A.dew point increase
B.dew point decreases
C.relative humidity increases
D.relative humidity decreases
