能出现反常呼吸的肋骨骨折是（）
A.两根肋骨骨折
B.两根以上肋骨骨折
C.双侧肋骨单根骨折
D.多根多处肋骨骨折
E.多发性肋软骨骨折
参考答案：D
He plans to have a__________ vacation. He thinks he'll be__________
when he returns. [ ]
A. relaxing; relaxing
B. relaxing; relaxed
C. relaxed; relaxed
D. relaxed; relaxing
“网络的价值等于网络节点数的平方”是( )
A．达维多定律
B．梅特卡夫定律
C．边际收益递增规律
D．摩尔定律
