中等强度体力劳动的特点是
A．氧需等于氧上限
B．氧需不超过氧上限
C．氧需超过氧上限
D．氧债几乎等于氧需
E．氧债等于氧需
参考答案：B
His school reports said that he is always ready to __________ a challenge.
A．receive
B．get
C．accept
D．gain
运行中振动筛应检查的部位有哪些？
