1．random adj.　　　　随意的

　　2．estimate n．& vt. 估计，估算

　　3．imply vt. 暗示；意味着

　　4．due to 因为，由于

　　5．extensive adj. 广泛的，全面的

　　1．Why does the number of languages climb steadily over the course of the twentieth century?

　　__________________________________________________________

　　2．What is the authoritative number of languages?

　　__________________________________________________________

　　__________________________________________________________

　　【答案】　1.Because our increased understanding of how many languages are actually spoken in areas that had previously been under described.

　　2．6,809.

Section Ⅰ　

Welcome to the unit & Reading－Preparing

　　根据提示写出下列单词

　　1．________ n． 词汇

　　2．________ adv. 现在，如今

　　3．________ vi. 组成，构成

　　4．________ n. 混合，混合体

5．________ vt. 养育，培养；举起； 增加，提高；筹募；提及