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1．Which floor do they start from?
| A．The first floor. | B．The second floor. | C．The fourth floor. |
| A．Technology in the old days. | B．Inventions in different centuries. | C．Modern inventions in the 20th century. |
| A．On the first floor. | B．On the second floor. | C．On the fourth floor. |
| A．Searching the Internet. | B．Asking the guide for help. | C．Buying books or magazines. |
| A．A guide. | B．A teacher. | C．A worker. |
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
