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1．How old is Davyon?
| A．13 years old. | B．11 years old. | C．7 years old. |
| A．He helped Bill leave the burning house. |
| B．He got the bottle cap out of Bill’s throat. |
| C．He called the fire department. |
| A．Sitting in his mother’s car. | B．Playing basketball. | C．Playing with his RC car. |
| A．Give more examples of young people. |
| B．Present Davyon with a certificate. |
| C．Play a video of Davyon. |
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
