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Our life changed a lot. Many years ago, people read books to get new information（信息）. They often went to the library and stayed there for a long time. But it was difficult for them to find the information. It took them a lot of time. Now, we can learn on the Internet. We don’t need to go out. We can study at home and learn by the computer. We can learn easily and quickly.
Now we have a lot of ways to learn. But I still like reading books best. Because a nice book is a good friend.
| Then | Now |
| People got the new information from | Many people get the new information from the |
| We usually spent a lot of | We study at home and learn |
| It was | We learn in an |
| There are a lot of | |
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
