GB/T17913-1999《粮食仓库磷化氢环流熏蒸装备》中要求环流风机应保证粮堆气体交换次数为()。
A、2次/日
B、4次/日
C、5次/日
D、10~15次/日
参考答案:D
阅读以下对话,选出所给问题的正确答案。
Wu Yifan: Excuse me, how can I get to the zoo?
Policeman: Are you going on foot?
Wu Yifan: Yes.
Policeman: Turn left at the library. Then go straight to the traffic lights. Turn left at the school. That's Shengli
Street.
Wu Yifan: OK. Then what?
Policeman: Walk straight for three minutes. The zoo is on the right. You can see it.
Wu Yifan: Thank you very much.
Policeman: You are welcome.
1. — How does Wu Yifan go to the zoo? — He goes to the zoo ____________.
A. on foot
B. by bike
C. by bus
2. When (当……的时候) he gets to the library, he should ____________ the traffic light.
A. turn left at
B. go straight to
C. turn right at
3. The zoo is ____________ of Shengli Street.
A. on the left
B. in the middle
C. on the right
近年来,航空公司为争抢客源,实行机票打折优惠。2010年五一期间,在竞争最激烈的某航线上,特价机票降至低于火车硬卧车票票价,使得不少原打算坐火车出行的人改乘飞机。这种现象说明
[ ]
A.价格是由需求决定的
B.价格是受消费者制约的
C.在互为替代的两种商品中,消费者对现实商品的需求,受二者价格变动的影响
D.消费者对商品的选择,受服务质量的影响