问题1：定义以下术语。
(i)线段
(ii)共线点
(iii)平行线
(iv)相交线
(v)并发线
(vi)雷
(vii)半线
解决方案：
(i) A line segment is a one-dimensional line connecting two points. It is the shortest distance that is incident on both the points.
(ii) Two or more points incident on the same line are called collinear points.
(iii) Parallel lines run opposite each other and do not intersect each other at any point of time.
(iv) Intersecting line segments are a pair of lines meeting each other at a common point, which is also called a point of intersection. Both the lines are incident on this point.
(v) Two or multiple line segments that are incident on a common point, are called concurrent lines.
(vi) A ray is a line segment that is fixed on one end and indefinitely extending on the other.
(vii) Let us assume A, B, C be the points on a line, such that A lies mid-way between B and C. If we delete the point A in between from B and C from the line, the two parts of l remain are each called a half-line.
问题2：
(i)一条给定点可以穿过多少条线?
(ii)两条不同的线最多可以相交多少个点?
解决方案：
(i) An infinitely large number of lines can pass through a given point
(ii) Two distinct lines at the most intersect at one point.
问题3：
(i)给定两个点P和Q。找出它们确定的线段数。
(ii)命名由三个共线点P，Q和R确定的线段。
解决方案：
(i) One line segment is incident on the points P and Q.
(ii) PQ, QR, PR are line segments determined by the three collinear points P, Q and R.
问题4：编写以下每个语句的真值(T / F)：
(i)两点相交在一个点上。
(ii)两条线可以相交于两个点。
(iii)段没有长度。
(iv)两个不同的点总是确定一条线。
(v)每条射线都有一个有限的长度。
(vi)射线只有一个端点。
(vii)一个网段只有一个端点。
(viii)射线AB与射线BA相同。
(ix)给定点只能通过一条直线。
(x)如果两条线只有一个共同点，则它们是重合的
解决方案：
(i) False
(ii) False
(iii) False
(iv) True
(v) False
(vi) True
(vii) False
(viii) False
(ix) False
(x) False
问题5：在下图中，命名为：
(i)五个线段
(ii)五缕
(iii)四个共线点
(iv)两对不相交的线段
解决方案：
(i) Five line segments, namely, AB, CD, AC, PQ and DS respectively.
(ii) Five rays : PA, RB, DC, QS, DS
(iii) Four collinear points, namely, C, D, Q, S respectively.
(iv) Two pairs of non–intersecting line segments, which are AB and CD, PB and LS respectively.
问题6：填写空白，以使以下说法正确：
(i)平面中的两个不同点确定_____________线。
(ii)飞机上两个不同的___________不能有一个以上的共同点。
(iii)给定一条线和一个点，而不是在该线上，只有一条_____________线穿过给定点，并且_______________到给定线。
(iv)一条线将飞机分成_________个部分，即__________和_____本身。
解决方案：
(i) unique
(ii) lines
(iii) perpendicular, perpendicular
(iv) three, two half planes, line.