热水锅炉在确保安全的前提下长期连续运行,在额定供回水温度、压力和循环水量下,每小时出水的有效带热量为锅炉的()供热量。
A、额定
B、常规
C、连续
D、平均
参考答案:A
Zhang Yining has trained continuously for six hours. _____ she is tired out.
A.There is no wonder
B.There is no need
C.It’s no wonder
D.It’s no doubt
步进炉的优点是什么?