Which is not the tunnel type?

A. soft ground tunnel
B. medium-hard rock tunnel
C. hard rock tunnel
D. narrow tunnel

Which is not the tunnel structure?

A. circle structure
B. rectangular structure
C. horseshoe structure
D. steel structure

Many countries are using tunnel to provide spaces for human activities not include（）

A. storage
B. living
C. war
D. transportation

A construction method for tunnel is called NANM, its full name is （）

NATM construction process contains（）、（）、（）、（）