平均世代年数(mean longth of generation, LG)

1、For means of abandonment of a ship，whi

For means of abandonment of a ship，which type of embarkation does not require prior approval by the Coast Guard?（）AMovable laddersBFixed laddersCSafety boomsDElevator

2、世代交替(alternation of generation)

世代交替(alternation of generation)

3、世代交替（alternation of generations）

世代交替（alternation of generations）

4、The purpose of DC generator brushes is

The purpose of DC generator brushes is to （）.Aneutralize armature reactionBconduct electric current to an outside circuitCconvert DC current to AC currentDprovide excitation to a DC generator

5、The voltage output of an AC generator

The voltage output of an AC generator is controlled by（）Avarying the DC exciter voltageBvarying the reluctance of the air gapCregulating the speed of the prime moverDshorting out part of the armature winding

6、The frequency of an AC generator is ad

The frequency of an AC generator is adjusted by means of the （）Amain alternator field rheostatBexciter field rheostatCprime mover governor controlDequalizing reactor