起重机吊钩断裂会导致重大的人身及设备事故。下图所示为几种吊钩的断面。其中,只允许用于小型起重设备的吊钩是()断面的吊钩。
A.圆形
B.片式
C.梯形
D.T字形
参考答案:A
—Who is the man talking to the detective?
—Maybe he is one of the ________ who is asked to tell what he saw. [ ]
A. witness
B. suspects
C. actress
详述酶的大分子修饰中非共价修饰和共价修饰?