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问题 单项选择题

现有一由Na2S、Na2SO3、Na2SO4组成的混合物，经测定硫的质量分数为 25.6%，则此混合物中氧元素的质量分数为( )。

A．37.6%
B．36.8%
C．25.6%
D．51.2%

答案

参考答案：A

选择题

最早提出“一切人生来就是平等的”这一观点的文献是

A．英国《权利法案》

B．美国《独立宣言》

C．法国《 * * 宣言》

D．《 * * 党宣言》
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改错题

下列各句中各有一处错误，找出并改正。

( )1. A girl name Jane gave you a call this morning. 

                                                                                                        

(     )2. All the boy students are enjoying to swim in the river.

                                                                                                         

(     )3. Thank you for come to see me.

                                                                                                          

(     )4. There's going to have a meeting tonight.

                                                                                                          

(     )5. All the food are on the table and the candles are on the cake. 

                                                                                                          

(     )6. My mother isn't here. She may be is in the study. 

                                                                                                          
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