问题
单项选择题
牙釉质的无机化合物主要是
A．磷酸钠
B．磷酸钾
C．碳酸钾
D．磷酸钙
E．磷酸镁
答案
参考答案：D
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牙釉质的无机化合物主要是
A．磷酸钠
B．磷酸钾
C．碳酸钾
D．磷酸钙
E．磷酸镁
参考答案：D
| 阅读下列两篇短文，从各小题所给的四个选项中选出能够回答所提问题或完成所给句子的最佳答案。 | ||||||||
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| 1. Annie gets _____ progress in learning English. | ||||||||
| A. excellent B. poor C. good D. alittle | ||||||||
| 2. Which of the following sentences is NOT true? | ||||||||
| A. Annie is a Crade 9 student. B. Annie is a lazy student in Thomas's opinion. C. Annie gets some of the English skills. D. Annie does better in German than geography. | ||||||||
| 3. Annie does worst in _____. | ||||||||
| A. math B. history C. science D. English | ||||||||
| 4. Annie's vacation will last _____. | ||||||||
| A. about one month B. more than two months C. over two months D. less than one month | ||||||||
| 5. There are _____ of Annie's classmates doing betterthan her in her class. | ||||||||
| A. none B. five C. ten D. one | ||||||||