盛含有机氯农药水样的样品瓶要待采水样荡洗3-3次。
参考答案:对
PPPOE完整交互过程的顺序是()。
A.PADI->PADR->PADO->PADS->PADT
B.PADI->PADO->PADR->PADT->PADS
C. PADI->PADO->PADT->PADS->PADR
D.PADI->PADO->PADR->PADS->PADT
In Britain,sales of cigarettes have been reduced __________ 30% in the past ten years.
A.for
B.to
C.from
D.by