实践证明,在切削限度内,叶轮切削前后水泵效率变化不大,因此切削抛物线也称
A. 等效率曲线
B. 管路特性曲线
C. 水泵特性曲线
D. 叶轮变速曲线
查看答案
调速后的转速能与其临界转速重合、接近或成倍数
A. 对
B. 错
切削调节中叶轮的切削量是有一定限度的
A. 对
B. 错
A shop assistant is presenting a new model language translator to hercustomer. Listen to theconversation and choose the points the woman mentionsin her description.Language Translator Model Latest□Attractive shape □Weight:80g□Two colors □ Length: 12cm□ Safe to use □ Width: 6cm□ Easy to use □ Height: 3cm□ Advanced technology □ Power: 40w□ Reasonable price □ Languages: 5
Asalesgirlisintroducingoneoftheirprinterstoacustomer.Listentotheconversationandfillintheblankswithwhatyouhear.M:Couldyougivemethesizeoftheprinter?W:Yes.It’s15centimeters___________________.M:Howaboutits___________________?W:It’s30centimeterswide.M:Howlongisit?W:The___________________is___________________centimeters.M:Bytheway,howmuchdoesitweigh?W:Its___________________is5kilograms.