问题
单项选择题
地球上已找到的属于原核生物的微体化石（即最原始的形式）距今的年龄是（）。
A、4.5Ga；
B、3.8Ga；
C、3.5Ga；
D、3.0Ga
答案
参考答案：C
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地球上已找到的属于原核生物的微体化石（即最原始的形式）距今的年龄是（）。
A、4.5Ga；
B、3.8Ga；
C、3.5Ga；
D、3.0Ga
参考答案：C
| 短文改错。 | |
| High school in the United States is usually dividing into Two periodsthe first two and three years is called "junior high school" and other is "senior high school". In China, children enjoy free education of nine year, but in the United States, the students enjoy free education until they are of eighteen years old. American children have little difficulty go to senior high school. American high school students could take part in a lot of activity outside of the classroom. The school organize the activities such as joining a music group or a sports team. Certainly, just like we students in China. | 1._________ 2._________ 3._________ 4._________ 5._________ 6._________ 7._________ 8._________ 9._________ 10.________ |