闭式系统的喷头,其公称动作温度宜高于环境最高温度()。
A.20℃
B.25℃
C.30℃
D.35℃
参考答案:C
解析:闲式系统的喷头,其公称动作温度宜高于环境最高温度30%。
12.I have written down everything that I saw and heard____memories are still fresh.
A.since
B.while
C.before
D.Unless
焊接接头由()和焊接热影响区组成