洗车指数是根据过去12小时和未来48小时有无雨雪天气，路面是否有积雪和泥水，是否容易使汽车溅上泥水，是否有沙尘等天气条件，给爱车族提供是否适宜洗车的气象指数。洗车指数共分为4级，级数越高，就越不适宜洗车。读“2015年4月6日17时某区域地面天气图”，完成下列各题。

材料一：上课时老师提供一则材料：某网站围绕“我的小康生活”话题展开讨论。

材料二：***在十九大开幕式上作了题为《决胜全面建成小康社会 夺取新时代中国特色社会主义伟大胜利》的报告。***在报告中指出，让贫困人口和贫困地区同全国一道进入全面小康社会是我们党的庄严承诺。

已知2是关于x的方程x-2a=0的解，则a的值为（　　）

    One day, a lady on a carriage saw a young man walking on the rocky road.1 the young man didn't wear shoes and it seemed that there was 2 wrong with his feet.

    She asked the driver3him up, and said she would pay4 him. Then she asked the young man 5. He said he was going for the nearest sea-port, to offer himself as a sailor.

    Twenty years 6 on the same road, a sea-captain 7 was on a carriage saw an old lady walking along, and he made the driver stop his horses. He pulled up8old lady, saying, “I'll pay the money.”

    After 9 on the carriage, the old lady thanked the captain, “for,” said she, “I am10 poor to pay for a ride now.” The captain said, “I remember, twenty years ago when I was a poor man, near this very place, I 11 a ride on a carriage along the road by a kind lady.” “Ah,” she was 12“I am that lady! But things13with me since then.” “Well”, said the captain, “I have made some money, and have come home to enjoy it. I 14you twenty-five pounds a year if you accept my offer.” The  old lady's eyes were full of tears, and 15accepted the sailor's offer.

化学符号是学习化学的重要工具。
（1）用化学用语(化学符号)表示：①一个硫酸根离子____；②五个银原子____ 。
（2）写出下列符号中数字的意义：①3Cl^-____；②____ 。