标题: 问大家一道题 [打印本页] 作者: elusive 时间: 2016-3-21 01:56 标题: 问大家一道题 The infant mortality rate has decreased steadily over the past decades and is now at a lower rate than ever before.
(A) now at a lower rate than
(B) now lower than
(C) now a lower rate than
(D) presently lower than it was
(E) presently lower than the rate was
ever before到底用什么时态啊，是过去时态还是完成时态。
如果是完成时态，E选项改成“presently lower that the rate bas been"是不是就对了。