养殖水体浮游动物可用0.3~0.5ppm敌百虫杀灭;蓝藻、浮游植物,用()硫酸铜杀灭。
参考答案:0.7ppm
—What do you think of our plan?
—It will certainly ______; it is a great idea.
A.turn into
B.pay back
C.pay for
D.pay off
移动电话拨打港澳台电话,在每天00:00—07:00按()。
A、标准价的80%
B、标准价的20%
C、标准价的50%
D、标准价