With the help of high technology,more and more new substances[ ]in the past years.空中应填have been discovered而不是 had been discovered,为什么

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/28 02:23:22
With the help of high technology,more and more new substances[ ]in the past years.空中应填have been discovered而不是 had been discovered,为什么
x) ,P(HUH)POSL &gW*$(y ťI%yɩ y`% EzWzc]S.\XY_ZɎg3+d$K<ٱ';;li:r~`§zmx:gų9O[7?| h ɦ%_oڷiDL[V<]aލO'

With the help of high technology,more and more new substances[ ]in the past years.空中应填have been discovered而不是 had been discovered,为什么
With the help of high technology,more and more new substances[ ]in the past years.
空中应填have been discovered而不是 had been discovered,为什么

With the help of high technology,more and more new substances[ ]in the past years.空中应填have been discovered而不是 had been discovered,为什么
和现在有关的用have
和现在无关的用had
过去发现的物质对现在有影响,所以用have