tunnel through mountains and cut across ridge

例句：

1. 1. The tunnel is so narrowthat only one person can pass through ata time.
   这个隧道太窄了，只能一个人一次通过。
2. 2. The tunnel was builtto help flood victims reach safety.
   这个隧道是为了帮助洪水受害者到达安全地带而建造的。
3. 3. The tunnel is the only wayto get to the other side of themountain.
   这个隧道是通往山另一边的唯一途径。