题目内容

在用来发射卫星的火箭头部涂了一层特殊的物质。这种物质可以避免火箭因高速运动与空气作用产生高温而被毁坏的危险。这种材料能起这种作用的主要原因是()

A. 材料受热熔化并汽化时吸收了与空气作用产生的热
B. 材料不传热
C. 材料非常光滑,不易与空气作用生热
D. 材料坚硬,不怕热

查看答案
更多问题

什么是创卫?

A salvor may be()the whole or part of the payment due under Salvage Convention to the extent that the salvage operations have become necessary or more difficult because of fault or neglect on his part or if the salvor has been guilty of fraud or other dishonest conduct.

A. granted of
B. deprived of
C. awarded of
D. taken away

怎样拍摄黑化头像?

拍摄人像怎样确定照相机的高度?

答案查题题库