A.bh3/12 B.bh3/6 C.bh2/12 D.bh2/6
A.1 B.2 C.3 D.4
A.離左支點(diǎn)L/4處 B.離左支點(diǎn)L/2處 C.離左支點(diǎn)3L/4處 D.離左支點(diǎn)L/3處