语法与词汇
Within the foreseeable future there may be a major ______of species, involving from one-third to two-thirds of all the species now in existence.
【正确答案】
D
【答案解析】在不久的将来可能会有物种的灭绝，包括现存的1／3～2／3的物种都会濒临灭绝。这道题考查学生辨别形近词的能力，这四个词长得很像，但意思却大相径庭：exhaustion 耗尽，exhibition展览，extension拓展，extinction灭绝。