A.鋼筋混凝土結(jié)構(gòu) B.鋼結(jié)構(gòu) C.砌體結(jié)構(gòu) D.木結(jié)構(gòu)
A.60mm B.70mm C.80mm D.100mm
A.50mm B.60mm C.70mm D.80mm