工人们正在挖掘隧道以建造一条新的地下通道。

The workers are ___tunneling to create a new underground passage.

工程师们正在山底下挖掘隧道以修建新的铁路。

Engineers are ___tunneling under the mountain to build a new railway.

工人们正在为地铁项目日夜不停地挖掘隧道。

The workers are ___tunneling day and night for the subway project.

使用SSH隧道可以安全地在公共网络上传输敏感数据。

SSH ___tunneling allows secure transmission of sensitive data over public networks.