不属于克雷伯菌属生物学特性的是 （）

A.接种环挑取黏液性菌落时呈长丝状

B.有荚膜，无鞭毛

C.鸟氨酸脱羧酶阳性

D.脲酶阳性

E.触酶阳性

A change of trim may be simply defined as（）.

A.the change in difference between the forward and aft drafts

B.the sum of free communication, free surface and pocketing

C.the moment of inertia of the ship's waterline plane about the athwartship axis

D.rolling and listing