13. For each of the following words and phrases, give one word or short phrase (of not more than seven words) which has the same meaning that the word or phrase has in the passage. (a) hijack (line 3) (b) vulnerable (line 10) (c) vigilant (line 10) (d) hostages (line 15) (e) on their guard (line 20) (f) bulky (line 32) (g) go to extraordinary lengths (line 53) (h) without incident (line 58) ​