A.上弦節(jié)點(diǎn)間 B.上弦節(jié)點(diǎn)處 C.下弦節(jié)點(diǎn)間 D.下弦節(jié)點(diǎn)處
A.0.93 B.0.95 C.0.96 D.0.98
A.3mm B.5mm C.8mm D.以上答案都不對(duì)