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"My grandma lives in a village. The rivers there are very clean. She often washes clothes by a river. I hope the rivers in our city can also be clean, " a student from Hangzhou wrote in his report(报告).
In Hangzhou, some primary school students took part in a survey(民意调查). They tested the water of the rivers near their homes and schools. They tried to find out what made the rivers dirty. Then, they wrote reports about that.
Now some students go to clean the rivers at weekends. And they also stop other people from throwing rubbish into the rivers. I think we can learn from them.
1．The rivers in the student's grandma's village are dirty.2．Some middle school students took part in a survey.
3．The students wanted to find out what made the rivers dirty.
4．They made a poster after the survey.
5．Some students stop other people from throwing rubbish into the rivers.
同类型试题
y = sin x， x∈R， y∈[–1，1]，周期为2π，函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x， x∈[–1，1]， y∈[–π/2，π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
y = sin x， x∈R， y∈[–1，1]，周期为2π，函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x， x∈[–1，1]， y∈[–π/2，π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
