insulate和isolate在做“隔离，孤立“解时，有何区别
insulate:
动词，将…隔离(以免受外界影响)。
词根: insul =island,表示“岛屿,sul有’单独’之意“
1. protect from heat, cold, noise, etc. by surrounding with insulating material;
““We had his bedroom insulated before winter came.“
2. place or set apart;
“ They isolated the political prisoners from the other inmates.“
isolate:
动词，使孤立;使脱离(朋友、支持者)。
词根: sol 1. =alone,表示“单独“; 2. =sun,表示“太阳“
1. place or set apart;
“ They isolated the political prisoners from the other inmates.“
2. obtain in pure form;
“The chemist managed to isolate the compound.“
3. set apart from others;
“The dentist sequesters the tooth he is working on.“
4. separate (experiences) fromt he emotions relating to them
经济学中“positive”和“normative statements”有什么区别
positivestatements是实证陈述，讲的是客观事实，可以理解为“是什么”。比如：“我国的税负比美国高。”
normative statements是规范陈述，含有主观的价值判断，可以理解为“应该怎么样”。比如：“我国的税负太高了（应该低一点）。”
因此，经济学也可以按以上标准分为实证经济学（positive economics）和规范经济学（normative economics）。
Positive statements are descriptive.They make a claim about how the word is.
例子：Minimum-wage laws cause unemployment.
Normative Statements are prescriptive.They make a claim about how the would ought to be.
例子：It is immoral for the government to kill people.
angular的中文翻译是什么
angular 英[ˈæŋgjələ(r)] 美[ˈæŋɡjəlɚ]
adj. 有角的; 用角测量的，用弧度测量的; 生硬的，笨拙的; （人） 瘦削的;
[例句]He had an angular face with prominent cheekbones.
他的脸棱角分明，颧骨突出。
-ul
