Graph paper, parallel, and planimeter methods are current tools for acreage calculation.

目前常用的量算积方法有方格纸法、法、积仪法。

Parallel lines are lines that never join.

是永不相交的。

Parallel lines are, by definition, lines on the same plane that never join.

按照定义说, 是在同一上永不相交的。

Zollner's illusion makes parallel lines seem to diverge by placing them on a zigzag-striped background.

将置于锯齿形条纹背景上，左氏错觉会看起来不。

There are two parallel lines.

这有两条。