单项选择题
After the trouble of the automatic control system has been completely eliminated, assistance is （） required.
A.remained B.still C.no longer D.much mere
单项选择题 （） is the actual value of the controlled condition.
单项选择题 Which of the following marine examples belongs to the open loop control system?（）
单项选择题 The operation of （） two alternators requires the voltages to be equal and also in phase.
