照明种类可分为( )。
A．局部照明； B．事故照明； C．警卫照明； D．障碍照明。
参考答案：B,C,D
慢性化脓性骨髓炎瘘管经久不愈的原因是（）
A.骨质增生
B.脓腔或死骨存在
C.骨干增粗
D.新生骨形成
E.骨髓腔闭塞
We don't have to ______ every word that we don't know when reading. [ ]
A. look up
B. refer to
C. look for
D. look into
