Read the text below and fill in the gaps using the clues given in the boxes. There are more words than necessary. One word can be used once only. the, knew, earth, true, in, atmosphere, lightning, when, aeroplane, kill, or, occur

Lightning is a giant spark (a) —— the sky. This spark may (b) —— between a cloud and the (c) ——
between a cloud and air (d) —— between two different clouds. The (e) —— spark is produced in the
(f) ——. It may damage a flying (g) ——. The lightning spark that hits (h) —— earth may cause fires or
(i) —— people and animals. But people (j) —— little about the reality of lightning till 1752 AD.