问题
单项选择题
为确保安全和节能，锅炉结垢后应及时清除，承担锅炉酸洗除垢的单位应（）
A、经合同签定
B、经上级主管部门同意
C、经国家级行业协会资质评定
D、自行清洗
答案
参考答案：C
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为确保安全和节能，锅炉结垢后应及时清除，承担锅炉酸洗除垢的单位应（）
A、经合同签定
B、经上级主管部门同意
C、经国家级行业协会资质评定
D、自行清洗
参考答案：C
| 阅读下列短文，从每小题所给的A、B、C、D四个选项中选出最佳选项。 | ||||
| Hill is from Canada. He is thirteen years old. He is a student of a middle school. It's 1 Monday. Hill 2 to school at 8:15 in the morning. He has English classes at 8:30. He likes English 3 it is interesting. At eleven he has math classes. Hill doesn't like it very much because it's 4 . 5 favorite subject is P.E., because the class is funny. He has P.E. 6 Monday afternoon. So, Hill 7 Manday very much. On weekdays, from Monday to 8 , Hill always has 9 at school at 12:00. After school, Hill usually plays 10 on the school playground. Then he goes back home at 4:45 p.m. His school life is very interesting. He likes his school very much. | ||||
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