Which one is not forbidden in the cabin during the flight? (飞行中下面哪种行为是允许的?)
A. Reading magazines.
B. Making a phone call with a mobile phone.
C. Playing with a remote control toy.
D. Using a walkie talkie.
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If you feel bad when the plane lands or takes off, what can you do? (如果在飞机起飞或降落时,你觉得不舒服,可以怎么做?)(多选题。)
A. Chew gum.B. Open the mouth.C. Talk with the neighbor.D. Walk in the aisle.E. Open the window.
B. Open the mouth.
C. Talk with the neighbor.
D. Walk in the aisle.
E. Open the window.
定向凝固要设法提高定向凝固的固-液界面附近液相中的温度梯度GL。
A. 对
B. 错
下列属于区熔法的单晶生长的方法为 ( )。
A. 坩埚移动法
B. 型壳移动法
C. 晶体提拉法
D. 悬浮区熔法
GL / R 值是控制晶体生长形态的重要判据。
A. 对
B. 错