All lightning,the bright flashes of light in an electrical strom,has one form although observers might say that they have seen four different kinds.One type,the most common,is called forked,zigzag,or chain lightning.It is truly a chain of light,streak of brightness that travels instantly through the dark sky following a meandering path,changing its course in many directions like a river.Sheet lightning occurs below the horizon in relationship to the observer.Heat lightning,the same as sheet lightning,is common on a summer evening.Because heat lightning is not always associated with rain,it has been given a separate lable by observers.The fourth and rarest kind of lightning is balll lightning,so called because it resembles balls of fire with three to five seconds duration,These balls of fire fall from the clouds,strike the ground,and explode within a short time.Some experts have doubted the stories of fire balls although they have had to believe the testimony of reliable witnesses.As one scientist said,when the major of the town,three school teachers,and a judge say that they have seen a fire ball,it is hard to say that they are all imagining it.
连连看(下列字母是上文着色单词的解释，但顺序已打乱。请找出正确的对应关系，按数字顺序重新排列字母)
a.something that serves as evidence
b.a close observer; someone who looks at something
c.appear like; be similar or bear a likeness to
d.any event that usually accompanies or is closely connected with another
e.the period of time during which something continues
f.resembling a fork; divided or separated into two branches
g.conforming to fact and therefore worthy of belief
h.to move or cause to move in a sinuous, spiral, or circular course
1.Lightning is __.
A.zigzag lightning B.the bright flashes of light in an electrical storm C.sheet lightning D.ball lightning
2.Meandering means in the selection __.
A.river B.a meandering path C.through the dark sky D.changing its course in many direction
3.Duration means __.
A.a length of time B.a kind of lightning C.an explosion D.a lightning cloud
答案：BDA fhdceagb