问题补充:
With the help of high technology, more and more new substances in the past few years.
A. discovered
B. have discovered
C. had been discovered
D. have been discovered
答案:
A. discovered
B. have discovered
C. had been discovered
(答案→)D. have been discovered
解析:考查时态。根据时间状语in the past few years,说明使用现在完成时。根据句意说明使用被动形式。句意:因为有高科技的帮助,早最近几年中,越来越多的物质已经被发现了。故D正确。