You’ve probably heard of working dogs that help police officers, or horses that help farmers. Did you know that carrier pigeons（信鸽）can be trained to help people too? Here are some examples.
Mailman
Carrier pigeons can be trained to carry messages to people. The note is placed into a small can. The can is tied to the pigeon’s leg. Then the pigeon flies off with the note.
Lifeguard
From high up in the sky, specially trained pigeons can find orange life jackets in the ocean. Sometimes it is difficult for humans to find people lost at sea, especially when the weather is bad. However, pigeons can fly quickly over a large area of water to look for people.
Spy
Many years ago, carrier pigeons were used to help our country during wars (战争). “Spy pigeons” had small cameras that were tied to their feet. As a pigeon flew over enemy (敌人)land, the camera took photos of the land below. This would allow our soldiers to see where the enemies were and what they were doing.
So next time you see a pigeon, stop and watch it closely. What might look like an ordinary bird to most people, might actually be helpful.
小题1:Which part of the carrier pigeon is the can tied to?
A．The pigeon’s back.
B．The pigeon’s head.
C．The pigeon’s neck.
D．The pigeon’s leg.小题2:What kind of people can the carrier pigeons find?
A．The people in orange life jackets at sea.
B．The people in red jackets in the boats.
C．The people swimming in the ocean.
D．The people lost in the mountains.小题3:Which of the following statements is TRUE according to the passage?
A．A pigeon could predict what the weather would be like.
B．A pigeon was tied with a small camera around its leg.
C．A pigeon could help us to know the number of the enemy.
D．A pigeon carried the camera to take photos of the enemy land.小题4:What kind of jobs are mentioned for a carrier pigeon?
A．A mailman, a lifeguard and a spy.
B．A trainer, a spy and a police officer.
C．A soldier, a police officer and a mailman.
D．A farmer, a weather reporter and a lifeguard.小题5:What is the purpose of writing this article?
A．To make readers like pigeons more.
B．To teach readers about the lives of wild pigeons.
C．To tell readers about real jobs held by carrier pigeons.
D．To share science fictions about pigeons helping people.
×100%进行分析判断。苯丙氨酸中碳原子的相对原子质量之和为12×9＝108，氢原子的相对原子质量之和为1×8＝8，氧原子的相对原子质量之和为16×2＝32，氮原子的相对原子质量之和为14，碳元素的相对原子质量之和最大，根据化合物中元素的质量分数＝