30. 主機轉速 100 rpm.
(A) Pitchesof the propeller are 100 per minute.
(B) Revolutions of the auxiliary engine are 100 per minute.
(C) Revolutions of the main engine are 100 per minute.
(D) Revolutions of the electric engine are 100 per minute.

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統計： A(2), B(6), C(16), D(2), E(0) #1229151