A：维护公平
B：维护正义
C：明辨是非
D：为人正直
小球从离水平地板3m高处沿竖直方向自由下落，被水平地板弹回，在离水平地板2m高处被接住，共用时间1.25s，则在这个过程中小球的平均速率和平均速度的大小分别是（ ）
①是有限责任公司回报投资者的体现
②有利于提高上市公司的盈利水平
③有利于调动资本市场投资者积极性
④是投资者股票收益的重要组成部分
用“>” “<” “=”填空
①50mL酒精与50mL水混合后体积____ 100mL.
②50℃时熟石灰的溶解度____20℃时熟石灰的溶解度.
③20℃时40g氯化钠加入100g水中，充分搅拌，形成溶液的质量____140g.
(20℃时氯化钠的溶解度为36g)
④20℃时KNO3的溶解度为31.6g,则20℃时其饱和溶液的溶质质量分数____31.6％.
In America, there are chores(杂活) for children of different ages. American people think that it's important to tell children their duty in the family.
Ages 4-6
Ages 6-12
Ages 13 and Up
-Make their bed;
-Clear dishes from the table;
-Set the table;
-Get the mail from the mailbox;
-Take care of pets;
-Cook simple food;
-Help wash the car;
-Vacuum(吸尘) and sweep;
-Take out the rubbish.
-Wash windows;
-Clean out fridge;
-Prepare a meal;
-Make shopping lists;
-Mow the lawn(剪草坪)
