Senna leaf does not contain any very hairy leaves(Cassia auriculate),the absence of which is demonstrated in the following manner．In the sentence"which"refers to（）

A:Senna leaf B:following manner C:Senna leaf and cassia auriculate D:Senna leaf and any very hairy leaves E:any very hairy leaves

The elephant is the only animal in the world with a trunk (the very long nose of an elephant), It uses its trunk (21) many ways. It (22) leaves off trees with its trunk and then puts them into its (23) . It can even uses its trunk to pull up trees when it wants to make a path through a jungle (热带丛林). It also uses its trunk to get (24) . The trunk can hold a lot of it, (25) an elephant needs to drink more than three hundred pints(品脱) of water every day. It has been easy for men to train elephants. All the elephants are considered useful in India (26) for white elephants. They are used to carry things for long distance in Indian forests. Many people say that some ancient Indian kings used to give white elephants to people they did not like. These white elephants were regarded as (27) animals. They could not be gave (28) to work. A person who owned a white elephant had to (29) a lot of money to keep it properly. After a certain time, he usually became very (30) . Nowadays people in England call a useless thing "a white elephant".

30（）

A:leaves B:food C:grass D:water

Every summer in Australia there is the danger of bush fires. Long periods of hot dry weather cause the grass and trees to become highly inflammable. In addition to the dryness and high temperature, another important factor is the great amount of oil in the leaves of such trees as eucalyptus, gum and ti trees.
Fires start very easily, often spontaneously(自动地，自发地), but usually because of a carelessly thrown cigarette or match. If there is a high wind, the ample supply of air fans the flames into an inferno. The radiant heat vaporizes the oil in the leaves; and the fire travels very quickly, sometimes overtakes fleeing cars and burns passengers to death.
Great fires often occur around Christmas, in areas near big cities, causing great loss of life and property.
According to the passage, fires erupt when ______.

A:arsonists set matches to leaves B:crude oil contacts inflammable objects C:tourists throw cigarette ends onto refuse dumps D:trees start burning of themselves

The elephant is the only animal in the world with a trunk (the very long nose of an elephant), It uses its trunk (21) many ways. It (22) leaves off trees with its trunk and then puts them into its (23) . It can even uses its trunk to pull up trees when it wants to make a path through a jungle (热带丛林). It also uses its trunk to get (24) . The trunk can hold a lot of it, (25) an elephant needs to drink more than three hundred pints(品脱) of water every day. It has been easy for men to train elephants. All the elephants are considered useful in India (26) for white elephants. They are used to carry things for long distance in Indian forests. Many people say that some ancient Indian kings used to give white elephants to people they did not like. These white elephants were regarded as (27) animals. They could not be gave (28) to work. A person who owned a white elephant had to (29) a lot of money to keep it properly. After a certain time, he usually became very (30) . Nowadays people in England call a useless thing "a white elephant".

28（）

A:leaves B:food C:grass D:water

The elephant is the only animal in the world with a trunk (the very long nose of an elephant), It uses its trunk (21) many ways. It (22) leaves off trees with its trunk and then puts them into its (23) . It can even uses its trunk to pull up trees when it wants to make a path through a jungle (热带丛林). It also uses its trunk to get (24) . The trunk can hold a lot of it, (25) an elephant needs to drink more than three hundred pints(品脱) of water every day. It has been easy for men to train elephants. All the elephants are considered useful in India (26) for white elephants. They are used to carry things for long distance in Indian forests. Many people say that some ancient Indian kings used to give white elephants to people they did not like. These white elephants were regarded as (27) animals. They could not be gave (28) to work. A person who owned a white elephant had to (29) a lot of money to keep it properly. After a certain time, he usually became very (30) . Nowadays people in England call a useless thing "a white elephant".

22（）

A:leaves B:food C:grass D:water

Halloween is an autumn holiday that Americans celebrate every year. It means "holy evening", and it comes every October 31, the evening before All-Saints Day. It used to be thought the most wonderful night of the year. It was the night when witches and evil spirits came back on earth. People kept up many strange old customs in an effort to keep these evil things away. Farmers used to light big fires in their fields, and the farm workers and their families would walk around the fields singing old songs. Sometimes they would stop to hear the local priest offer prayers to the good spirits, and ask them to help keep the evil ones away.
Great care was taken that none of the farm animals were left in the fields. They would all be locked up safely in their stables, and over each of the stable doors a few rowan leaves would be hung. Witches and evil spirits would not go anywhere near the rowan tree.
In more recent times, Halloween has become a time for the parties, when children dress up as witches and play all kinds of special games. After the games there is often a big supper with plenty of pumpkin pie, cakes and a lot of other delicious things to eat.
But for the most part the children enjoy the fun of dressing up and playing their favorite game of "Trick or Treat". They run down each street knocking on the doors crying loudly "Trick or Treat! Money or eat!", and most people have some sweets or money ready to give them. Those that do not can expect maybe to have a tyre flattened, or their windows covered in soap. Or the children may just knock on the door and run away.
Some children think of other people on Halloween. They carry boxes for UNICEF (The United Nations International Children’s Emergency Fund). They ask for money to help poor children all around the world. Of course, every time they help UNICEF, they usually receive a treat for themselves, too.
Every autumn, when the vegetables are ready to eat, children pick large orange pumpkins. Then they cut faces in the pumpkins and put lights inside. It looks like there is a person looking out of the pumpkin! These lights are called jack-o’-lanterns, which means "Jack of the lantern". But in this modern age many of the pumpkins are being replaced with plastic electric ones that can be brought out each year.
Why did people hung rowan leaves over the stables

A:Because farm animals liked rowan leaves. B:Because rowan leaves would keep witches and evil spirits away. C:Because they used the leaves to decorate the stables. D:Because rowan leaves could keep the farm animals quiet in the stables.

Many science reports discuss medical studies that test the effect of a new drug. Usually, a large number of people is divided into two groups. Each group takes a different substance. But no one knows which group is getting which substance. One group takes the medicine being tested. Another group takes what we call an inactive substance. Medical researchers call this substance a "placebo." The word "placebo" is Latin for "I shall please." Placebo pills(宽心丸)usually are made of sugar.
Using placebos to test drugs sometimes has a surprising result. Researchers say people taking the placebo often report improvements in their health. This is known as "the placebo effect"--pain that is eased or stopped by an inactive substance. In such testing, the drug must perform better than the placebo to prove that it is effective.
Doctors have reported that the placebo effect can be used in treatment. For example, a doctor tells a patient that a new drug will stop the pain in his leg. The pill is only sugar. But the patient does not know that. He takes the pill and says his pain is gone.
Scientists are beginning to discover some physical reasons for this reaction in some people. They are learning that much of what people believe to be true comes from what the brain expects is going to happen. If the brain believes a drug will ease pain, the brain may begin physical changes in the body that can cause the expected effect. A recent examination of studies on drugs for depression found that placebos eased the depression about as well as the active drugs.
Other studies have explored the power of placebos. A study in Japan involved thirteen
people who reacted to the poison ivy (常青藤)plant. Poison-ivy causes red itchy sores(伤痕)on some people who touch it. Each person was rubbed on one arm with a harmless leaf, but was told it was poison ivy. Each person was then touched on the other arm with poison ivy, but was told it was a harmless leaf. All thirteen people developed a reaction on the arm where the harmless leaf touched their skin. Only two reacted to the poison ivy leaves.
Doctors and scientists worry that the use of placebos may not always be harmless. They say people can become victims of false doctors and others who use placebos to claim they can cure disease.
What do medical researchers usually use to make placebo pills

A:Ivy leaves. B:Harmless leaves. C:Medicine being tested. D:sugar.

{{B}}第三篇{{/B}}

The last paragraph is mainly about ______.

A:the comparison between plants in different areas B:the growth of new leaves in the rainy season C:water loss by evaporation in the dry season D:the changes in the leaves of the perennials

{{B}}第三篇{{/B}}

What do medical researchers usually use to make placebo pills?

A:Ivy leaves. B:Harmless leaves. C:Medicine being tested. D:sugar.