【简答题】键能是化学键强弱的量度,键能越大,表明该化学键越______,即断裂该键所需的能量______。
【多选题】用标准齿条形刀具范成加工标准齿轮时,关于根切产生原因叙述正确的是_______。
【单选题】The experiment turned out to be a complete failure, _____ wasn’t _____ they expected.
【单选题】用齿条形刀具范成加工标准齿轮时,齿轮产生根切的原因是( )。
【简答题】Listenand complete the following message. To:______________ From:___________ Company:___________ Message:______________
【单选题】— Why didn’t they complete the task in time? — Because it was not until late afternoon _____ they began to solve the major problem.