单项选择题
With reference to a two ram actuating mechanism, which one of the following statement is false?（）
A.The rams work inside cylinders B.The cylinders have glands sealing their open ends C.The rams are connected to a cross-head D.The cross-head is mounted on the rudder stock
单项选择题 The DC excitation to the field of brushless synchronous is generally produced by （）
单项选择题 Which of the following equipment is not pollution prevention equipment?（）
单项选择题 The initial voltage of self-excitation generator set up by（）
