什么是重点旅客？
参考答案：
重点旅客指老、幼、病、残、孕旅客。
– How do you find this film? - It is the best film .
A．that I had seen
B．which I have ever seen
C．which I saw
D．that I have ever seen
在蒸发浓缩中，加热温度和加热时间是不可分割的，尽可能保证食品品质要______加热，而提高生产效率要加热。
