【判断题】拉(压)杆的内力与轴线重合,称为轴力,符号规定拉为负,压为正。()
【单选题】I’m afraid you have got a lot more questions to ___ me again.
【单选题】意大利旅行家马可·波罗在游记中称元大都为“世界莫能与比”,请问是现在的()
【单选题】The old man keeps coughing________. I’m afraid you have to send him to hospital.
A.
between morning to night
C.
between morning and night
D.
from morning and night
【判断题】在一定接触时间内,一定反应温度和反应物配比下,主反应的转化率愈高,说明催化剂的活性愈好。
【单选题】– My bike is missing. I can’t find it anywhere. – I’m afraid you have to buy .
【单选题】意大利旅行家马可·波罗在游记中称为“世界莫能与比”的元大都,就是今天的( ):
【判断题】轴向拉压杆正应力正负号规定:拉为正,压为负。
【单选题】—Hello! May I speak to Lucy,please? —Sorry,I’m afraid you have the wrong .