最近在搞prep08，语法笔记上好多解释都不懂~比如这题

majestywhite

The widely accepted big-bang theory holds that the universe began in an explosive instant 10 to 20 billion years ago and has been expanding ever since.

A.that the universe began in an explosive instant 10 to 20 billion years ago and has been expanding

B.that the universe had begun in an explosive instant 10 to 20 billion years ago and had been expanding

C.that the beginning of the universe was an explosive instant 10 to 20 billion years ago that has expanded

D.the beginning of the universe to have been an explosive instant 10 to 20 billion years ago that is expanding(A)

E.the universe to have begun in an explosive instant 10 to 20 billion years ago and has been expanding

prep08：

C选项中：the beginning of the universe was an instant主语和表语搭配错误；was应该改为is；that has expanded修饰instant错误

这题目选A。

我不理解的是C中的was为什么要改成is？？不是有XX years ago 么。

且A中的began也是过去式啊~~~

如果说描述自然现象用一般现在时，为何A中是过去时？

may24

个人理解，the beginning of the universe是一件事，可以做一般事实处理，而A中the universe是一个东西，描述这个东西如何肯定就要遵循时态了

milymilychen

同意楼上MM的！