A.脊節(jié)點(diǎn) B.中央節(jié)點(diǎn) C.端節(jié)點(diǎn) D.角節(jié)點(diǎn)
A.受彎 B.受拉同時(shí)受彎 C.受壓同時(shí)受彎 D.受剪
A.1/200 B.1/300 C.1/100 D.1/400