奥氏体不锈钢压力容器作水压试验时，水的氯离子含量不得超过（）g／m3
A、40
B、50
C、25
D、30
参考答案：C
书面表达。
阅读下面的短文，然后按提示写一篇读后感。可适当发挥。词数：100左右。
提示：
1. 概括短文的内容要点；
2. 你认为可以采取哪些措施，从“我”开始，节约用水。
Recently, the World Forum on Water Resources has suggested that all countries take action to
deal with the global water crisis. Millions of people worldwide currently face water shortages.
Some poor countries suffer from periodic droughts. Almost half of the population in developing
countries are suffering from diseases caused by untreated water. Poor quality water is a threat to
humans’health at any time.
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数据库系统的基本特征是( )。
A．数据的统一控制B．数据共享性和统一控制C．数据共享性、数据独立性和冗余度小D．数据共享性和数据独立性
