It is often difficult for a man to be quite sure what tax he 9ught to pay to the government be-cause it depends on so many different things: whether the man is married; how many children he has; whether he supports any relations; how much he earns; how much interest he receives; how much he has spent on his house during the year, and so on and so forth. All this makes it difficult to decide exactly how much the tax is.
There was a certain artist who was always very careful to pay the proper amount.
One year, after posting his check as usual, he began to wonder if he had paid enough, and after a lot of work, with a pencil and paper, he decided that he had not. He believed that he owed the government something.
He was just writing another check to send to the tax-collector when the postman dropped a letter into the box at the front door. Opening it, the artist was surprised to find inside it a check for five pounds from the tax-collector. The official explained that too much had been paid, and that therefore the difference was now returned to the taxpayer.
It is mentioned in the passage that one has to pay tax according to______.

A bike tour and race will be held on July 26 and 27 ( Sat. & Sun. ). At 4:30 a.m. the riders will leave Tiananmen Square and ride the first 35 kilometers as a training leg. Then the next 55-ki-lometre leg, from Yanjiao to Jixian, will be the first competitive (竞争性的) part of the tour. The riders and their bikes will then be taken from Jixian to Changli.
The second racing leg of the tour will be from Changli to the seaside at Nandaihe, covering a distance of 20 kilometers. Saturday night includes the stay at Nandaihe and supper. Sunday morning is free at the seaside. At noon ail the people and their bikes will be taken back to Beijing.
Cost: 200 yuan
Telephone: 4675027

Brazilian footballers
The Brazilian Football Club will play Beijing Guoan Team at the Workers Stadium on July 26. The club has several national team players. Also coming is 1994 US World Cup star Romario who has promised to play for at least 45 minutes.
Ticket prices: 60 yuan, 100 yuan, 150 yuan
Time/Date: 4:30 p. m. , July 26 ( Sat. )
Telephone: 5012372

Rock climbing
The Third National Rock Climbing Competition will be held on July 26～27 at the Huairou Mountain climbing Training Base. More than 10 teams from Beijing, Wuhan, Daiian, Jilin and other places will take part in it. A Japanese team will give an exhibition of climbing. Free for spectators (观众).
Take a long-distance bus from Dongzhimen to Huairou.
Time/Dates:9～12 a. m. , July 26 and 27
Telephone: 7143177, 7144850, Wang Zhenghua

[A] was the heaviest one in the history
B. happened in Missouri and Illinois states
C. happened in less than 20 percent of the states of the USA
D. was recorded several times