Key to Exercises of College English Book 2Unit 1 Text A VocabularyI. 1.1) insert 2) on occasion 3) investigate 4) In retrospect 5) initial 6) phenomena 7) attached 8) make up for 9) is awaiting 10) notin the least 11) promote 12) emerged2. 1) There is a striking contrast between the standards of living in the north of the country and the south. 2) Natural fiber is said to be superior to synthetic fiber. 3) The citys importance as a financial center has ev