使酶具有高催化效率的主要因素有()()()()。
参考答案:酶与底物的靠近及定向效应;酶与底物发生变形作用;共价催化;酸碱催化
– ________ do you exercise?
– I used to exercise every day, but now I exercise twice a week.
A. How often B. How soon C. How long
怎样利用压铅丝法来测量轴承径向间隙的?