下部量代表
A．骨盆的发育B．脊柱的发育C．下肢长骨的发育D．腹腔脏器的发育E．下肢肌肉的发育
参考答案：C
To keep healthy, Professor Johnson _______ cycling as regular form of exercise after he retired.
A．tookup
B．caughton
C．carriedon
D．madefor
为了保证吊机的安全，当卷筒壁较原来厚度减少（）时，应报废是不正确的。
A.5%
B.7%
C.10%
D.15%
