【单选题】带有第三滚筒的制动试验台,制动力最大值取相对滑移率为( )时测量值。
【单选题】Why are Europeans particularly concerned with building materials?
A.
Lots of building materials there are radioactive.
B.
Up to 90% of them stay home.
C.
They have a high rate of lung cancer.
D.
They spend most of their time indoors.
【简答题】The use of new building materials and the introduction of such new technologies as the elevator and the air-conditioner have played an important role_____
【判断题】用同一结构声名的两个结构变量之间可以直接赋值