题目内容：

Most people would say the sea is blue and green. But the people who live near the coast of Zhejiang may say it is red. It is not people who caused the colour change, but very small living thing in the sea. They are algae（藻类）and protozoa（原生动物）. They come in many different colours: red, yellow or brown. Red is the easiest of those to see, so when this happens, people call it a “red tide.”

Red tides only happen when conditions in the sea are right. In the past few years, factories and people have been putting more chemicals into the sea. These chemicals help algae and protozoa to grow very quickly. The temperature of the sea is also important. Red tides usually happen at 20 to 30 degrees Celsius（摄氏的）. Red tides often happen in dry, warm areas where there is little wind. Living things grow easily in these places. Sometimes fishermen help red tides by mistake. They put small sea animals into the water for food to help fish grow.

Those living things do more than change the colour of the water--they also put poison and mucus（黏液）into the sea. This is bad for fish. The poison is bad for their brains. And too much mucus in the sea fills up fish’s gills（鳃）, so they can’t breathe. Lots of dead fish and other sea animals are now washed up on Chinese beaches.

Red tides can be bad for people, too. The algae gets inside of fish and it smells bad. It can make your eyes water. If people eat fish with too much algae inside, they could die.

Fishermen in Zhejiang are having a hard time right now. Because of the red tide, they are selling 30% less fresh seafood than usual.

In China, red tides usually happen in May and June around places like Fujian, Guangdong and Hong Kong.

Many other countries sometimes also have red tides. But it seems that we have few ways to stop red tides. They can last as long as 16 months.

1.What can cause the water in the sea to change its colour?

A. Algae.    B. Algae and protozoa.

C. Protozoa.    D. People and animals.

2.Which of the following is NOT true?

A. Fishermen in the area sell less fresh seafood than usual.

B. People could die if they eat fish with too much algae inside.

C. Algae and protozoa can’t give off any poison and mucus into the water.

D. Eating fish with algae in them can make people’s eyes water.

3.Which of the following is not a cause of red tides?

A. People catch too many fish and eat too much seafood.

B. People and factories put more chemicals into the sea.

C. The temperature is at 20 to 30 degrees Celsius.

D. It is dry and warm and there is little wind in the area.

4.What does the passage mainly tell us?

A. Don’t eat any fish with algae and mucus inside.

B. People should do their best to protect the sea.

C. The scientists have found good ways to stop red tides.

D. The forming of red tides and their harmfulness.