15.Bar codes are one way that the U.S.Postal Service streamlines mail of the wrong hands.A letter that comes without a bar code or cancelled stamp might not have been processed by the U.S.Postal Service and it might indicate that something's fishy.(可疑的)Can you decode a bar code the way the U.S.Postal Service can?
Here's How
1.Here's how to read the bar code on your letter.
•Most U.S.letter bar codes have bars of two lengths:long and short.
•Every bar code should start and end with long bars; ignore those.
•Look at the rest of the bars in groups of five,starting with the second bar.Each group of five represents one digit.(數(shù)字)
2.Here's how to figure out what those digits are.
•The five bars stand for one of these numbers:7,4,2,1,0.
•Some genius figured out that this range would allow you to come up with the digits 0to 9.You do it by adding the numbers of the long bars together.
Say you have this bar code:
Here,the 4and 2places have long bars.Added together,they total 6,so this bar code stands for 6.
Say you have this bar code:
The 1and 0places have long bars.Added together,they total 1,so this bar code stands for 1.
Say you have this bar code:
The 7and 4pieces have long bars.Added together,they total 11,but there is no 11in this system,so this bar code stands for 0.
3.Now let's look at the bar code on a letter.
Ignore the first and last bars of the whole bar code.Then look at the next 20bars to find the zip code (0680).The next two sets of five bars give your mail carrier's number (10153).The rest of the bars in the bar code indicate the house or maibox number.The house number is 32.
63.Why does US Postal Service just use five numbers for the five bars?D
A.They are easy to read. B.They are ohosen only by accident.
C.They can stand for the long bars. D.They are enough to make ten digits.
64.Which of the following bar codes otands for"7"according to the text?B
A.
B.
C.
D.
65.According to the text,we know thatC.
A.the bar code often beings with a short bar
B.the last short her is often ignored
C.the mail route should follow the zip code
D.the bar code can show your house color
66.The purpose of the text is to let us know how toB.
A.create a bar code B.recognize a bar code
C.send a letter D.make the maibox safe.