急性化脓性骨髓炎X线片变化多出现在起病（）。
A.1周后
B.2周后
C.3周后
D.4周后
E.5周后
参考答案：B
微型电脑用网卡
The teacher gave us ______ on how to study chemistry. [ ]
A. many advice
B. a few advice
C. few advice
D. much advice
