Fish extracts oxygen from water using ______.

A dolphin(海豚) looks more like a fish than certain fishes do. It is an excellent swimmer. The dolphin seems to flash through the water. Like fish, dolphins are completely at home in the water. There they play, feed, sleep, and give birth to their young. Dolphins live in the sea and can live only in the sea.

Yet they are not fish. A dolphin must come to the surface to breathe. Fish can take oxygen from the water.

Dolphins cannot. Like us, they breathe with lungs and must take their oxygen from the air. And they are mammals (哺乳动物).

Most mammals are land animals. Dolphins are evolved (进化) from land animals. Long ago, dolphin ancestors (祖先) left the land for the sea. Among the animals was a kind that would become the dolphin we know. No one is sure exactly what kind of animal it was. But there is reason to think it was related to grass-eating animals like the cow. Modern dolphins are fish-eaters. Yet their stomachs are like those of animals that eat plants. The make-up of their blood is also like that of grass-eating animals.

The best title for this passage is______.

A．Dolphins

B．Fish

C．Mammals

D．Cows

On April 1st in France, a person with a cardboard fish hooked to the back is called____________.

A、dies

B、is going to die

C、won't die

D、will die

听力原文： Fish live in water, but do they drink it? The answer is yes, but how fish drink water depends on where they live. Water gets into a fish's body through osmosis. Take a cell as an example, if there is more water outside of a cell than inside, water will try to flow into the cell until there is the same concentration of water on either side of the cell's membrane. The body of a fish acts the same way, (33) either absorbing or losing water depending on its surroundings.

Whether a fish absorbs or loses water is based on the fact that all fish must maintain a certain amount of salt in their bodies to stay healthy. (34) Fish that live in fresh water have a higher concentration of salt in their bodies than the surrounding water. Consequently, water continuously flows into the fish's body to attempt to dilute the amount of salt in the fish until it is equal to the amount of salt in the surrounding water.

Ocean fish have the opposite problem. Surrounded by salt water, their bodies contain a relatively lower concentration of salt than the ocean water. In this case osmosis causes the fish to constantly lose water in order to equalize salt concentration inside and outside the fish. To partially compensate for the water loss, ocean fish actually drink water through their mouths. And (35) to get rid of the excess salt they take in by drinking seawater, they excrete some salt through cells in their gills.

(30)

A．Water absorbing ability.

B．The cell's membrane.

C．Its surroundings.

D．The ability to maintain salt.

A．Fish have difficulty absorbing oxygen in warmer seawater.

B．The seawater temperature is increasing.

C．Fish have trouble finding enough food in warmer seawater.

D．More fish have to find another location.

The world itself is becoming much smaller by using modem traffic and modem communication means. Life today is much easier than it was hundreds of years ago, but it has brought new problems. On, of the biggest is pollution. To pollute means to make things dirty. Pollution comes in many ways. We see it, smell it, drink it and even hear it.

Man has been polluting the earth. The more people, the more pollution, many years ago, the problem was not so many people. When the land was used up or the river was dirty in one place, man moved to another place. But this is no longer true. Man is now slowly polluting the whole world.

Air pollution is still the most serious. It's bad for all living things in the world, but it is not the only one kind of pollution man makes. Water pollution kill our fish and pollutes our drinking water. Noise pollution make us angry more easily.

Many countries are making rules to fight pollution. They stop people from burning coal in houses and factories in the city, and from putting dirty smoke into the air.

Pollution by SO2(二氧化硫) is now the most dangerous kind of air pollution. It is caused by heavy traffic. It is sure that if there are fewer people driving, there will be less air pollution.

The earth is our home. We must take care of it. That means keeping the land, water and air clean. And we must take care of the rise in population at the same time.

Our world is becoming much smaller ______.

A．because the earth is being polluted day and night

B．thanks to science development

C．because of the rise in population

D．because the earth is blown away by the wind every years