[PAR] [TLE] Sydney Harbour Bridge [SEP] The Sydney Harbour Bridge is a steel through arch bridge across Sydney Harbour that carries rail, vehicular, bicycle, and pedestrian traffic between the Sydney central business district (CBD) and the North Shore.  The dramatic view of the bridge, the harbour, and the nearby Sydney Opera House is an iconic image of Sydney, and Australia.  The bridge is nicknamed "The Coathanger" because of its arch-based design. [PAR] [TLE] Sydney Harbour Tunnel [SEP] The Sydney Harbour Tunnel is a twin-tube road tunnel in Sydney, Australia.  The tunnel was completed and opened to traffic in August 1992 to provide a second vehicular crossing of Sydney Harbour to alleviate congestion on the Sydney Harbour Bridge.  It is the only tunnel under the harbour, although there are plans to build a set of rail tunnels.
[PAR] [TLE] Sydney Harbour Bridge [ SEP ] The Sydney Harbour Bridge is a steel through arch bridge across Sydney Harbour that carries rail , vehicular , bicycle , and pedestrian traffic between the Sydney central business district ( CBD ) and the North Shore . The dramatic view of the bridge , the harbour , and the nearby Sydney Opera House is an iconic image of Sydney , and Australia . The bridge is nicknamed " The Coathanger " because of its arch - based design . [PAR] [TLE] Sydney Harbour Tunnel [ SEP ] The Sydney Harbour Tunnel is a twin - tube road tunnel in Sydney , Australia . The tunnel was completed and opened to traffic in August 1992 to provide a second vehicular crossing of Sydney Harbour to alleviate congestion on the Sydney Harbour Bridge . It is the only tunnel under the harbour , although there are plans to build a set of rail tunnels .
While the Sydney Harbour Bridge is a steel through arch bridge, the Sydney Harbour Tunnel is what?
While the Sydney Harbour Bridge is a steel through arch bridge , the Sydney Harbour Tunnel is what ?
a twin-tube road tunnel
a twin-tube road tunnel