dam 堤，壩

collapse 崩潰，倒下

be destoryed by 被...摧毀

mine 我的，礦，地雷

miner 礦工

pose threat to 給...造成危害

assess 評(píng)估

too...to...太...而不能...

halt 停轉(zhuǎn)

investigation 調(diào)查

答案：AC