螺母的硬度应（）螺栓的硬度。
A．稍高于
B．等于
C．稍低于
D．高于
参考答案：C
雌激素活性最强的是（）
A.雌酮
B.雌二醇
C.雌三醇
D.环戊醚雌三醇
E.儿茶酚雌酮
--- Peter, you the window quickly, will you?
--- OK! Oh! The window broken.
A．shut; is
B．will shut; has been
C．are shutting; was
D．have shut; has been
