对系统性红斑狼疮关节痛描述不正确的是()
A.四肢大小关节均可出现疼痛
B.面部蝶形红斑是特征性改变
C.常伴有脱发
D.关节伸面有皮下结节
E.以女性青年多见
参考答案:D
It's 12 o'clock. Mary's family ______ their lunch. [ ]
A. eat
B. are eating
C. eating
D. to eat
按照《空气和废气监测分析方法》(第四版)中“气相色谱法测定非甲烷烃”的方法,使用的色谱柱为长1m、内径4mm的不锈钢柱。