语法综合练习7SalesofCD'shavegreatlyincreasedsincetheearly1990s,whenpeopletoenjoytheadvantageofthisnewtechnology.A.beginB.beganC.havebegunD.hadbegun请详细写出解题的过程和思路.

Question

语法综合练习7
Sales of CD's have greatly increased since the early 1990s,when
people ______ to enjoy the advantage of this new technology.
A.begin B.began C.have begun D.had begun
请详细写出解题的过程和思路.

Answer 1

选B,1990s就是一个过去时间概念,由when来引导,所以这里直接用过去时.