He sat back on the chair, took a book and began to read, ___.

A．being looked at ease

B．looked rather at ease

C．to look rather at ease

D．looking rather at ease

道岔开口方向上，道岔定位后应保证两线接触悬挂的任一接触线分别与相邻线路中心的距离不小于（）处。

A.1200mm

B.1220mm

C.1240mm

D.1250mm