钽、锆、铌及其合金用于压力容器受压元件时，铌和铌合金设计温度不高于（）℃。
A、200
B、220
C、250
参考答案：B
BIS
Which one of the following activities is included in the acquisition activities in the Natural Approach
A. Affective-humanistic activities. B. Communicative activities.C. Skill-getting activities. D. Social activities.
