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问题 单项选择题

急流滩的最显著的特点有（）。①过水断面急骤减小②形成局部陡比降③产生高速水流④流态紊乱⑤滩势强弱随水位变化⑥出现倒套

A.①②③④⑤⑥

B.①②③④⑤

C.①②③④

D.②③④⑤

答案

参考答案：B

完形填空

根据短文内容及首字母提示，填写所缺单词，使短文意思完整，每空限一词。(10分)

Teenagers live very busy lives now and often forget to think about their diets and exercise．The truth is, healthy eating along with regular exercise is the only way to k 小题1:      fit．

During your teenage years, it is important to give your body the energy it needs．Teenage g小题2:     need about 2,200 calories a day and boys need a bit m 小题3:     —doctors suggest 2,800 for teenage boys．50% of your calories should come f小题4:      rice, bread, vegetables and fruit．You also need to drink a lot of water, 6 to 8 glasses a day．Drinking e 小题5:  water will improve your skin and give you healthy hair．

E 小题6:      is something that can help to make you look good, feel good and be healthy．Experts(专家) suggest that teenagers s 小题7:      at least 30 minutes exercising, five times a week．W小题8:      you exercise, your body produces something that makes you feel r 小题9:．It can even help you sleep better at night and let you pay more a 小题10: when you study!
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单项选择题

结蜡抽油机井生产中，定期进行（），可以保持泵效。

A、保养

B、热洗

C、检泵

D、放气
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