1.
To arrange in or form a line.
排成直线，形成直线
2.
Line ab be twice longer than line cd .
直线AB比直线cd长2倍。
3.
in alignment (with...)
(与…) 成一直线
4.
Of, relating to, or resembling a line; straight.
线的，直的线的、与直线有关的或象直线的；直的
5.
In a vertical or perpendicular line.
垂直地在一条垂直线或竖直线上
6.
draw a line perpendicular to a given line
作一直线与已知直线垂直
7.
Arrangement or position in a straight line or in parallel lines.
直线排列直线或平行线的排列或位置
8.
In, of, describing, described by, or related to a straight line.
直线的直线本身的、直线的、描述直线的或用直线描述的或与直线有关的
9.
A vertical or nearly vertical line or plane.
垂直线，垂直面垂直或近似垂直的线或平面
10.
straight-in approach
(飞机) 直线进场
11.
out of alignment (with...)
(与…) 不成直线的
12.
conjugate lines in a conic
二次曲线的共轭直线
13.
ideal straight line
理想直线（线性ＡＤＣ或ＤＡＣ的）
14.
down-the-line shot
沿边线打击的直线球
15.
the movement of the pointer or pen of a measuring instrument from its zero position.
从直线或指定路线偏转。
16.
Radio waves travel in straight lines.
无线电波是直线传播的。
17.
Something vertical, as a line, plane, or circle.
垂直物垂直的东西，比如垂直线，垂直面或垂直圆
18.
Straight, closing and archipelagic baselines
直线基线、闭合基线和群岛基线