【简答题】18MnMoNB焊前预热的温度为( )A. A.小于50 ℃ B.50~100 ℃ C.100~150 ℃ D.大等于150 ℃
【单选题】要抽取矩阵 a 的对角元素应使用的命令是( )
【单选题】Which of the following is not mentioned as the difference between hostels and hotels?
A.
Hotels are usually larger than hostels.
B.
Hostels are cheaper and more informal than hotels.
C.
Hostels provide more adventurous travel than hotels.
D.
There is less privacy in a hostel than a hotel.
【判断题】渐进带为14mm的渐变焦镜片,所需要的最小框高为28mm
【单选题】Why do young people, especially backpackers, prefer hostels to hotels?
A.
Because hostels are more infomal than hotels.
B.
Because there are more opportunities for younle to socialize.
C.
Because hostels provide more adventurous travel than hotels.
D.
Because there is less privacy in a hostel than a hotel.
【单选题】渐进带为14mm的渐变焦镜片,所需要的最小框高为( )