better ways for digging tunnels, the first railway tunnel under the River Thames was dug i

better ways for digging tunnels , the first railway tunnel under the River Thames was dug in 1884.
A. As , developing
B. With, developed
C. As , were developed
D. With, development

A. As , developingB. With, developed(答案→)C. As , were developedD. With, development解析：考察as和with用法。As是连词表示随着；with是介词，后面接复合结构“with+宾语+宾语补足语”；本句可以使用“As better ways for digging tunnels developed”；也可以使用“with better ways for digging tunnels developing”；句意：随着更好的挖掘方法的改善，第一条泰晤士河底的隧道在1884年开通了。故C正确。

我明天再问问老师，叫他解释下这个问题