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Arbor Day
In America, people celebrate（庆祝） Arbor Day in April. This annual（每年的）holiday encourage（鼓励）people to plant and care for trees.
I received a tree seedling（幼苗）on Arbor Day when I was 7 years old. My parents helped me plant the little tree in our front yard（院子）. I was so proud of it! 25 years later, I an still proud when I see it! Now it is a tall tree.
America isn’t the only country to have a tree planting day. Korea and other countries, also have hold a national（国家的）tree planting festival.
1．American Arbor Day is in April.2．I planted a little tree 7 years ago.
3．There is a tall tree in our front yard now.
4．Korea is the only country to have a tree planting day.
5．America isn’t the only country to have a tree planting day.
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
