工业上应用最广的热冷流体热交换基本方式是
A. 对流传热
B. 直接接触式传热
C. 间壁式传热
D. 蓄热式传热
传热过程的推动力是
A. 热量差
B. 温度差
C. 内能差
D. 动量差
What is the writer doing in this text?
A. Describing a summer school he started in 2005.
B. Explaining how to send a child to Tinkering.
C. Talking about the US school system.
D. Talking about Tulley's programmes for kids.
What does the text say about safety at the school?
A. The school is too dangerous for kids.
B. No child has ever had an accident.
Children have never hurt themselves badly.
D. The school doesn't give information about that.
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