【单选题】关于电子商务的优势,下面哪个是错误的( )
【单选题】If a radial piston hydraulic pump fails to deliver rated fluid volume, the cause can be _____.
D.
obstructed suctions passage
【单选题】电路如图所示,则提供功率的电源是( )。
【单选题】An axial轴向 piston pump differs from a radial piston pump as the pistons of an axial piston pump are positioned ().
A.
radially from the shaft
B.
parallel to each other and to the shaft
C.
parallel to each other but at a right angle to the shaft
D.
at an angle to each other and to the shaft
【单选题】在丝锥攻入1~2圈后,应及时从()方向用90°角尺进行检查,并不断校正至要求。
【判断题】萘的化学性质以亲电取代反应为主,且主要发生在β-位
【单选题】With reference to a radial piston pump, which one of the following statements is false?
A.
Surrounding the fixed shaft is a hollow shaft
B.
This hollow shaft carries radial bores
C.
Each bore is fitted with a well-lapped plunger
D.
There are always even numbers of bores