题目内容：

The Yangtze is the longest river in China, _____which some more bridges have been built in the past few years.
A. onto B. through
C. above D. over
选哪个,解释以下原因

优质解答

D.over
which 指的是 Yangtze （长江）
桥在河上,介词用 over
请看例句：
There is a broken small old gray stone bridge over the river.
河上有一座破烂不堪的,古老的,灰色的小石桥.