以下几种材料中，（）粘接性能最差，是难粘材料。
A、ABS塑料
B、PA塑料
C、PP塑料
D、PVC塑料
参考答案：C
He is very popular among his students as he always tries to get them ________ in his lectures.
A．interesting
B．interested
C．being interested
D．to interest
某55岁男性，有高血压、冠心病史，左足怕冷疼痛，间隙性跛行年余。月余来足痛转为持续性静止痛，夜间痛剧，不能入睡，趺阳脉搏动消失。应诊断为（）
A.雷诺病（肢端动脉痉挛症）
B.脱疽
C.糖尿病坏疽
D.闭塞性动脉硬化症
E.足癣并感染
