Bombing had made roads and railways unusable.是什么意思？

Bombing had made roads and railways unusable.

轰炸导致公路和铁路都无法通行。

bombing

n. 轰炸，投弹；v. 轰炸，投弹于( bomb的现在分词 )，失败，不及格，快速前进；

例句
That statement seemed designed to answer criticism of allied bombing missions.
那份声明似乎是专门就联合轰炸任务的批评作出反击。

had

v. 有（ have的过去式和过去分词 ），（亲属关系中）接受，拿，买到；

例句
He claimed that his parents had abandoned him...
他声称父母遗弃了他。

made

adj. …制的，（人工）做成的，拼成的，虚构的，保证成功的；v. 使(make的过去式和过去分词)；

例句
Single people are treated as an aberration and made to pay a supplement.
独身者被当成异类，而且要付一笔额外的费用。

roads

n. 锚地，路( road的名词复数 )，通路，途径，方法；

例句
The roads are built to accommodate gradual temperature changes...
修建这些道路时考虑到了温度的逐渐变化。

and

conj. 和，与，而且，于是，然后，因此；

例句
I spend a lot on expensive jewelry and clothing...
我花很多钱购买昂贵的首饰和衣服。

railways

n. 铁路，铁道( railway的名词复数 )，铁路系统；

例句
...the conveyance of bicycles on Regional Railways trains.
通过地区铁路公司的火车运输自行车

unusable

adj. 不能用的；

例句
Mortality is the number or volume of trees periodically rendered unusable through natural causes.
枯损是一类由于自然原因而定期变得无用的林木株数或材积.