实名举报应在()天内将结果书面反馈给反映人。
A、15
B、25
C、30
D、30
参考答案:D
228. Oh, the classroom is so dirty. It needs ______ before we begin our class.
A.cleaned
B.being cleaned
C.to clean
D.Cleaning
论述冶炼洁净钢需要哪些技术措施?