题目

有一种氮的氧化物，氮和氧的质量比为7∶4，则此氮的氧化物的化学式为__________。 答案：N2O We talk about people being “colour-blind” but very few of us are. Even those who describe themselves as colour-blind are normally just colour lack. A strongly, colour-blind person will still be able to tell 20 different colours, compared to the 100 or so that normal-sighted people see.Pingelap, a tiny island in the Pacific, is a beautiful spot but one that has a’ genetic trouble. It is known as Colour-blind Island because so many people who live on this remote island can only sec in black and white.Not being able to see in colour is bad enough. But one is lander, Herrol, who’s a fisherman, also struggles in full sunlight because all he sees is a painful burnt-out image. “I find it difficult to go outside in the sun,” he says, “because when it’s sunny I cannot see to do my work.”But if being truly colour-blind is rare, why is it that around 10% of the population of Pingelap live in a totally black and white world?Well，we know that in 1780 the population of Pingelap was all but wiped out by a tsunami (海啸). As few as 20 people survived, one of whom was the king. It’s believed he had a genetic fault that causes colour-blindness and he passed this fault on to his many generations.There is one advantage. Herrol can see well, really well, in the dark. So when it gets dark, Herrol and his friends get in their boats and hunt flying fish. They hang up flaming torches and the fish are attracted to the flames. “This type of fishing is fun,” Herrol says, “especially if we catch plenty. So even though it’s hard work we enjoy it.”【1】What is Pingelap famous as?A. A tiny island.B. A beautiful island.C. A mentally troubled island.D. A colour-blind island.【2】What .can we infer about Herrol?A. He may stay at home when it’s sunny.B. He is interested in burnt-out images.C. He likes taking photos very much.D. He doesn’t live in Pingelap any more.【3】Why are about one-tenth of people in Pingelap seriously colour-blind?A. Because Pingelap often suffers from tsunamis.B. Because the king had an unlucky marriage.C. Because the king’s genetic fault played a role.D. Because the king made a serious mistake.【4】What would be the best title for the text?A. The island of colour-blindness.B. The disadvantage of Herrol.C. The history of Pingelap.D. The advantage of colour-blindness.