Do you have any foreign friends? Do you know their characteristics(特征)?
The Germans are very quiet and they always keep calm. They don't like to speak more words. They look very serious. They like different kinds of amusements. The Germans are very hard—working. They like tidiness, especially the women, who always keep their home clean.
In some ways, the Englishmen look the same as the Germans. They are very quiet and never talk too much with the strangers. They are really polite, so we often hear they say "Thank you."Or "Sorry."The gentlemen are also the Englishmen.
The French's holidays are very long. They like traveling and usually spend their long time staying in other countries. The Frenchmen are more outgoing than the Germans. It is very easy to make friends with them.
Compared to the Frenchmen, the Americans are more outgoing. And they are even opener than all of the Europeans. They don't like to depend on others. So it is very common that the students do part-time jobs in their free time. And in Americans' eyes, success is an important part in their life.

下列化学符号①NO₂  ②2NO   ③SO₄^2﹣ ④$\stackrel{+2}{M_{g}O}$中，数字“2”表示元素化合价数值的是（填序号，下同）　 ____；表示分子个数的是　 ____； 表示每个分子中所含某元素原子个数的是　 ____；表示一个离子所带的电荷数值的是 ____

进入5月份，全国各地中小学都举行了“感恩亲情，孝敬父母”的活动。孝敬父母（）
①人人都能做到 ②是中华民族的传统美德 ③是法律规定子女应尽的义务 ④是做人的本分