根据课文内容填空。

①____去花还在，____来____不惊。

②草芽尖尖，他对小鸟说：“____。”

③____，一日之计在于晨。

④____，始于足下。

①存款业务       ②贷款业务    

③结算业务      ④发行人民币

    Every school has its own rules. How many1 are there in your school? At some schools, the students2to wear uniforms on school days. But many students don't want to wear the school uniforms. They think the uniforms are the ugly3. But the school doesn't allow students to wear4own clothes at school. So some students draw cartoons or other famous singers on their5. They think it is very6 that all the students wear the same. It isn't very good that teachers and students are wearing7 . But most of the students8the rules. What do you think9? Do you10your school uniforms?

写出下列化学符号或符号的意义：

①氧元素____；②氦气____；③三个钠离子____；

④氧化镁中镁元素的化合价为+2价____；⑤2H____；

⑥3CO₂____；