问题 单项选择题

高温腐蚀,是指金属材料在高温下与环境气氛中的氧、硫、碳、氮等元素发生化学或电化学反应而导致的变质或破坏。
根据上述定义,下列属于高温腐蚀的是( )。

A.厨房中的铁锅放置时间长了就会生锈,影响使用
B.因直流电源设备漏电而对地下管道、贮罐、电缆等金属设施造成严重的腐蚀破坏
C.当铸件受到交替加热和冷却,容易发生肿胀现象,铸铁肿胀使铸件机械强度大大降低
D.由于细菌活动,导致土壤氧浓度、盐浓度、pH值等的变化,使金属材料受到腐蚀破坏

答案

参考答案:C

解析: 高温腐蚀的定义要点是:①金属材料;②高温下;③变质或破坏。A、B、D三项都不符合②,只有C项符合定义。

完形填空

阅读短文,根据短文内容及首字母提示,在空白处填入一个适当的单词。

Years ago in Scotland, the Clark family had a dream. The couple worked and saved, making小题1: p     for their nine children and themselves to travel to the USA. It had taken years before they saved enough money and got everything小题2: r        for the trip.

The whole family was excited about their new life. However, seven days 小题3: b________       they left for the USA, the youngest son was bitten by a dog. The doctor treated the boy, 小题4: b____      because there was a possibility of rabies(狂犬病), they would be kept away from others for fourteen days.

The family’s dream could not come小题5: t   __   . They would not be able to make the trip to America as they had planned. Watching the ship leave---without the Clark family, the father was quite 小题6: a      with both his son and God for their bad luck.

Five days later, a piece of sad news小题7: s   __   throughout Scotland---the strong and powerful ship, Titanic, had gone down, taking小题8: h        of lives with it. The Clark family was to have been on that ship, but because the son was bitten by a dog, they were left 小题9: b_____        in Scotland.

When Mr Clark heard the news, he thanked his son for saving the family. He thanked the God for小题10: t       a sad thing into a good one.

Although we may not always understand, all things happen for a reason.

问答题 简答题