Part I Writing (30 minutes)注意：此部分试题在答题卡1上。Directions: For this part, you are allowed 30 minutes to write a short essay on the topic of Due Attention Should Be Given to the Study of Chine. You should
PTC热敏电阻PTC是Positive Temperature Coefficient 的缩写,意思是正的温度系数,泛指正温度系数很大的半导体材料或元器件.通常我们提到的PTC是指正温度系数热敏电阻,简称PTC热敏电阻.PTC热敏电阻是一种典型具有温度敏感性的半导体电阻,超过一定的温度(居里温度)时,它的电阻值随着温度的升高呈阶跃性的增高. PTC热敏电阻组织结构和功能原理陶瓷材料通常用作高电阻的
There are two main hypothes when it comes to explaining the emergence of modern humans. The ‘Out of Africa’ theory holds that homo sapiens burst onto the scene as a new species around 150,000 to 200
