The usual number of single-acting pistons used in a variable stroke axial-piston pump is

A．3 or 5

B．5 or 7

C．7 or 9

D．9 or 11

[单选题]In a diesel engine, when refitting piston rings you should ①check the ring gap at the smallest diameter of the cylinder ②remove carbon from the ring grooveA．①B．②C．①②D．neither ① nor ②

[单选题]For one or two types of engine,the piston and rod can be withdrawn downwards from the cylinder into the crankcase and then out through （）.A . the cylinder coverB . the bottom of bed-plateC . the sumpD . the crankcase door

[试题](c) Acting as an external consultant to Semer, discuss the validity of the proposed strategy to increase gearing, and explain whether or not the estimates produced in (b) above are likely to be accurate. (10 marks)

[试题]D．espitethewonderfulactingandwell-developedplotthe_________moviecouldnotholdourattention.A．)three-hoursB)three-hourC．)three-hours’D)three-hour’s

[单选题]Rotating flyweights acting against spring pressure make a simple type of （）.A . governorB . safety valveC . reducing valveD . feed water regulator

[单选题]They went on ________ as usualA．workB．workedC．worksD．working

[单选题]A． actingB． relyingC． centeringD． cementing

[名词解释] 反式作用因子（trans-acting factor）

[名词解释] 顺式作用元件（cis-acting element）

[单选题]The usual address for a Web site is the(74)page address, although you can enter the address of any page and have that page sent to you.A．homeB．mainC．hostD．house