【单选题】The China International Search and Rescue Team has brought help and hope to people in disasters around the world since it( )18 years ago.
【简答题】The rescue team set out for the earthqueke-stricken area ______the constant aftershock.
【单选题】下列有关涡轮风扇发动机的说法错误的是?
D.
涡轮风扇发动机的涵道比越大表面流过外涵道的流量大,表面发动机由喷气排出产生的推力所占的比例小,发动机的经济性就越高
【简答题】A rescue team has been set up tohelp the people who became ____________ during the earthquake.A. meaningless B. homeless C. hopeless
【单选题】The China International Search and Rescue Team has brought help and hope to people in disasters around the world since it was ______ 18 years ago.
【单选题】A rescue team has been set up to help the people who became during the earthquake.
【单选题】下列关于焊接温度场说法错误的是______。
A.
正常焊接条件下,经过一定时间后,焊件上也会形成准稳定温度场。
C.
焊件上瞬时温度相同的点连接在一起而组成的线称为等温线。
D.
焊接时,焊件上各点温度一直随时间而变化,因此焊件上不可能形成准稳定温度场。
【单选题】下列关于焊接温度场说法错误的是____。
B.
焊件上瞬时温度相同的点连接在一起而组成的线称为等温线。
C.
正常焊接条件下,经过一定时间后,焊件上也会形成准稳定温度场。
D.
焊接时,焊件上各点温度一直随时间而变化,因此焊件上不可能形成准稳定温度场。
【单选题】下列关于焊接温度场说法错误的是( )。
A.
焊件上瞬时温度相同的点连接在一起而组成的线称为等温线。
B.
焊接时,焊件上各点温度一直随时间而变化,因此焊件上不可能形成准稳定温度场。
C.
正常焊接条件下,经过一定时间后,焊件上也会形成准稳定温度场。