周围神经疾病的病因（）
A.营养代谢
B.药物及中毒
C.血管炎
D.肿瘤
E.以上均是
参考答案：E
They often leave the boy alone at home. They think that he’s old enough to look after _____.
A．them
B．himself
C．themselves
D．him
炼厂中（）颜色的管线表示消防线。
A.红
B.绿
C.黄
D.黑
