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Is your schoolbag too heavy to carry? The e-schoolbag will help you.
In fact, the e-schoolbag should be called the e-textbook. It is a small computer for students. Heavy schoolbags are not good for them. But the e-schoolbag will change everything. It is light and small, but it can save all the things for study, like a textbook, an exercise book and so on. Students can also use the e-schoolbag to take notes or send emails to their teachers.
Some people say the e-textbook is good for the students’study, but other people say it is not good for students’eyes. I think only the time will tell.
1．An e-schoolbag is a small computer.2．The e-schoolbag is big but light.
3．E-schoolbags are designed (设计) for teachers.
4．Some people think the e-schoolbag is good for students’ eyes.
5．The e-schoolbag is small but useful.
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
