骨盆入口前后径的前端是（）.
A.耻骨联合下缘
B.耻骨联合上缘中点
C.耻骨联合上缘
D.耻骨联合下缘中点
E.耻骨联合后面中点
参考答案：B
He arrived early,____ to have a look at his favourite pop star.
A．hoping
B．to hope
C．having hoped
D．hoped
简述课堂问题行为的控制策略。
