切削用量是切削速度、进给量和背吃刀量的总称。
参考答案：对
现有1克、2克、4克、8克、16克的砝码各一枚，问在天平上能称出多少种不同重量
A．5
B．10
C．31
D．32
Passage 2
Which of the following diseases occurs more frequently in among Americans than in Britons as it is suggested Dr Marmot’s research a. Heavy drinking. b. Cancer. c. Heart disease. d. Insomnia.
