小强同学在下面的4个计算中:①(a-b)2=a2-b2、②(-2a3)2=4a6、③a3+a2=a5、④-(a-1)=-a+1,做正确的题目是( )(填题目序号)。
②④
根据句中所给汉语,完成下列句子。(每空一词,每空0.5分,共10分)
小题1:一旦吉姆下定决心,我们中没有人能说服他。
Once Jim , none of us can persuade him.
小题2:看起来似乎三分之一的游客死于酒店里的这场大火。
one third of the visitors were killed in the big fire in the hotel.
小题3:汤姆一听到他得了癌症,感觉自己好像已经被判了死刑。
After knowing that he’d got cancer, Tom felt as if he had .
小题4:听到她儿子上台执政的消息,她突然大哭了起来。
On hearing that her son came , the woman tears.
小题5:三分之二的村民在地震中遇难或受伤。
Two-thirds of the villagers during the earthquake last night.
在主轴( )调速范围内选一适当转速,调整切削量使之达到最大功率,机床工作正常,无颤振现象。
A.恒转矩
B.恒功率
C.恒电流
D.恒电压