市话全塑电缆的型号中绝缘层代号YP代表电缆绝缘层为()。
A.实心聚烯烃绝缘
B.泡沫聚烯烃绝缘
C.泡沫/实心聚烯烃绝缘
D.都不对
参考答案：C
—They are quiet，aren't they?
—Yes.They are accustomed ________ at meals.
A．to talk
B．to not talk
C．to talking
D．to not talking
隐孢子虫主要经过哪些途径传播（）
A.消化道
B.血液
C.空气
D.虫媒
E.口-肛性交
