She knew nothing about his journey _______ he was likely to be away for three months.

A．Except

B．except for

C．except that

D．in addition

导线的弧垂的定义以及其大小的影响是（）。

A.导线两悬挂点的连线与导线最低点的垂直距离，称为弧垂

B.弧垂对导线的受力情况影响不算太大

C.弧垂过大容易造成相问短路及其对地安全距离不够

D.弧垂过小，导线承受的拉力过大而可能被拉断，或致使横担扭曲变形

E.导线的弧垂是一档架空线内导线最低点与导线悬挂点所连直线间的最大垂直距离