锅炉如何进行风烟道的保养?
参考答案:
一个月以上的长期保养,应对风烟道内表面积灰进行清扫,且关闭所有风门、挡板;一个月以内的风烟道保养,则不必处理积灰等。
—Mike, do you know who wanted me on the phone?
—Sorry. I don’t know. I ________ a bath in the bathroom.
A.have had
B.was having
C.had
D.am having
干热风对小麦危害的关键时期是()
A、苗期
B、拔节期
C、孕穗期
D、灌浆期