下图为我国某地等高线地形与铁路线路分布图。据此完成下面小题。
A.鞍部 | B.山脊 | C.山谷 | D.陡崖 |
A.121米 | B.131米 | C.141米 | D.151米 |
①增加交通运输方式 ②缩短通行时间
③提高通行安全 ④降低线路坡度
A.①② | B.②③ | C.③④ | D.①④ |

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

