精氨酸酶催化L-精氨酸水解为L-鸟氨酸与尿素,属于()
A.绝对专一性
B.相对专一性
C.立体异构专一性
D.化学键专一性
E.族类专一性
参考答案:C
— Everyone must __________ the security check (安检) before getting on the plane at the airport.
— Yes. It’s necessary to ensure the passengers’ safety.
A.get through
B.get across
C.go through
D.go across
对某碳钢进行金相分析,发现其组织为珠光体+网状渗碳体,其中珠光体占93℅。问此钢含碳大约是多少?