（）是组成焊接结构的关键元件，它的性能与焊接结构的性能和安全有直接的关系。
A.焊缝
B.热影响区
C.焊接接头
参考答案：C
行走困难，户外活动需用双拐或他人帮助，部分日常生活需他人帮助的多发性硬化患者，其Hyllested的残疾分级为（）
A.一级
B.二级
C.三级
D.四级
E.五级
The dichotomy postulated by many between morality and interests, between idealism and realism, is one of the standard cliches of the ongoing debate over international affairs.
A．division into two parts
B．combination of two parts
C．disparity
D．contradiction
