为严格控制温度，应采取哪些措施？
参考答案：
1、除去反应热或适当采取加热措施；2、防止换热在反应中突然中断；3、正确选择传热介质；4、加强保温措施。
No matter how frequently ____, the works of Beethoven still attract people all over the world. [ ]
A. performed
B. performing
C. to be performed
D. being performed
机床夹具按其______程度，一般可分为通用夹具、专用夹具、成组夹具以及组合夹具等。
A．通用化
B．系列化
C．标准化
