high and low altitude of USA-美国的高纬度和低纬度

In the case of the altitude of the United States. State of Colorado is the symbol of high altitude and the Hawii that of low one.

speed of high and low-速度的快慢

Here we're talking about the running speed: the turtle is the symbol of the much lower one if it is being compared by that of  the leopard.This couple stamps show the high and low example in the nature world.

you're high as a mountain

sunrise and sunset-日出和日落

The beauty of the sunrise and sunset is a good demonstration of the theme: High and Low. When we sitting on the beach or standing on high mountain, we can see the sun  rise from the sea level higher and higher in dawn and sink into sea at dusk lower and lower...

sports related with high & low-和高与低有关的运动

The content of the stamps shows two different kinds of sports. One is high jumping, the another is diving under the water. Their actions and movements explain well the theme of high & low.

twilight switch (High Low light intensity)-开关（高低灯强）

Product types

The twilight switch, as the name suggests, once mounted and, if programmed, automatically goes into action with the arrival of the dark (dusk) and turns off with the arrival of dawn. It acts according to the brightness of the environment in which it is placed. Some models can also be programmed to blink in the sense that keep theenvironment in the dark or illuminated at random, as if to simulate the presence ofpeople who are not there, or go out after a few hours after dusk, without waiting for the arrival dawn.

population density-人口密度

Population density (in agriculture standing stock and standing crop) is a measurement of population per unit area or unit volume. It is frequently applied to living organisms, and particularly to humans. It is a key geographic term.Several of the most densely-populated territories in the world are city-states, microstates, micronations, or dependencies. These territories share a relatively small area and a high urbanization level, with an economically specialized city population drawing also on rural resources outside the area, illustrating the difference between high population density and overpopulation.