细菌对氨基糖苷类抗生素产生耐药性的主要原因是
A.细菌产生水解酶
B.细菌改变代谢途径
C.细菌产生钝化酶
D.细菌胞浆膜通透性改变
E.细菌产生大量PABA
参考答案:C
----It shouldn’t take long to clear up after the party if we all volunteer to help.
-----That’s right.______________.
A.Many hands make light work.
B.Something is better than nothing.
C.The more, the merrier.
D.The sooner begun, the sooner done.
马氏体是碳在γ-Fe中的过饱和固溶体。( )