如何简单测定地形坡度用一块硬纸板自制一个简易的半圆量角器，在量角器半圆的圆心处用图钉和一根小细线悬一重物，您站在山坡的一侧，双手握住量角器，使量角器的底边与山坡保持平行一致，读取细线经过量角器的刻度数，再从该刻度数中减去90°则为山坡的坡度。精密单点定位(Precise Point Position...2015-08-05
The Threat to KiribatiThe people of Kiribati are afraid that one day in the not-too-distant future,their countrywill disappear from the face of the ea...2015-08-05
You build your future. It isn't handed to you.未来靠自己努力，而非靠人施予。——《纸牌屋》Once you let the darkness inside, it never comes out.一旦你的心变黑暗了，想变回来就难了。——《绿箭侠》When...2015-08-05
Mother Nature Shows Her StrengthTornadoes(龙卷风)and heavy thunderstorms moved across the Great Lakes and into Trumbull County on Saturday evening.：The s...2015-08-05
The Beginning of DramaThere are many theories about the beginning of drama in ancient Greece. The on most widely accepted today is based on the assump...2015-08-05
1. cavity洞 穴I’m afraid there won’t be time to do aother tooth today, make sure you don’t eat anything like steaks for the next few hours,and we’ll fil...2015-08-05
