Mr Li ____ England.  He ____ London for  two weeks.

A．has been to; has been to

B．has gone to; has been in

C．has been to; has been in

D．has gone to; has been to

两平行线间的交叉渡线，线间距小于4.3m时，单开辙叉及锐角辙叉的“有害空间”在线路方向上部分或全部重叠。为保证轮对能安全通过，应采用缩小菱形锐角辙叉单开道岔辙叉咽喉的办法，以延长翼轨制约车轮走行的范围，缩短有害空间。