Rather than ___ on a crowded bus, he always prefers _____ a bicycle.
A.ride; to ride B.riding; ride C.ride; ride D.to ride; riding
—The light in the office is still on.
— Oh I forgot _______.
A.turning it off B.turn it off C.to turn it off D.having turned it off
Though he had often made his little sister ________, today he was made ________ by his little sister.
A. cry; to cry B. crying; crying
C. cry; cry D. to cry; cry
The teacher told them ______ make so much noise.
A.don’t B.not C.will not D.not to
According to the UN’s World Happiness Report for 2016, Denmark is officially the happiest country on Earth.Here is a list of reasons behind the happiness：
A different view of money
Danes tend not to be concerned with “keeping up with the Joneses”. 1.. Rather than buying the fanciest cars or the most expensive houses, Danish people spend money on leisure activities such as hobbies, outings with friends, or games.
An enjoyable job climate
2.. They also work, on average, 1,522 hours per year, which is lower than most countries. Not only does this give them more leisure time, it is not detrimental, as the average yearly income is $59,850. Besides, Denmark has the lowest income inequality and highest minimum wage in the world.
3.
The importance placed on human communication fosters a belief in one’s neighbors and a trust that if something bad were to happen, the community would come to help them. 94% of Danes report that they have somebody they could rely on in time of need.
A clean environment
The government encourages green policies，such as bicycling in cities, in order to cut down on harmful emissions. Like bicycling, many of these measures also have other benefits. 4.. In Denmark, levels of air pollution, water pollution, and agricultural pollution are also lower than most other countries.
5..
A.Somebody to lean on
B.Somebody to seek advice from
C.Danes have lower unemployment rates than most countries in the world
D.Instead, they view money as a kind of means to connect with other people
E.Cities where bicycling is common have less traffic, less noise, and healthier citizens
F.Looking over all these factors, it becomes apparent that almost anybody would love living in Denmark
G.Parks, neighborhoods, and cities can be enjoyed without worry of pollution－related illnesses like asthma or allergies
Sharks use their good sense of smell to search for prey（猎物）. But a new study shows that the rising levels of carbon dioxide in the ocean could reduce sharks' ability to find food. It's bad news for a healthy ocean. Sharks are top predators（掠食动物）and are like the ocean's weed controllers.
Dixson works at the Woods Hole Oceanographic Institution in Massachusetts. Her earlier work has shown that clown fish in acidifying（酸化的）water act strangely. "We want to expand this research to sharks .because we know how important it is for sharks to find their food through their sense of smell," said Dixson.
Her team started by placing sharks in each of three different pools for five days. Each pool had a different level of carbon dioxide in it. The first had the same amount as today's ocean water. The second had a level of carbon dioxide that scientists expect to reach by 2050. The third pool had the highest level of carbon dioxide that could develop by the year 2100.
Sharks weren't allowed to eat any food while in the pools. This made sure that they would be hungry. Then, Dixson released the sharks one at a time into a pool with two side-by-side streams of flowing water. In one stream, the researchers pumped water, in which a dead squid had been overnight. This water smelled strongly of the squid. The other stream contained ocean water with no scent（气味）. Because each stream flowed at the same rate and in the same direction, the squid smell stayed in its stream. The sharks could choose to swim in either stream.
Sharks that had been swimming for five days in pools of regular ocean water spent more than 60 percent of their time in the squid-scented stream. The same was true for sharks that had been in water with the carbon dioxide level that could develop by the year 2050. But sharks exposed to the highest level of carbon dioxide spent just 15 percent of their time in the squid-scented stream.
1.Why did the writer mention the sharks smell at the beginning of the passage?
A. Because the writer appreciates their ability to find food.
B. Because the writer considers them dangerous to human beings.
C. Because the writer intends to show how to control weed in the ocean.
D. Because the writer worries about the sharks in the ocean.
2.What is Paragraph 3 mainly about?
A. What the ocean in the future will be like.
B. Who helped Dixson conduct the study.
C. What kinds of pools were used during the study.
D. What the levels of carbon dioxide will be at in the ocean in the future.
3.The researchers pumped water where a dead squid had been overnight to ______.
A. help the sharks look for food
B. test the sharks' sense of smell
C. prove that sharks like eating squids
D. explain why carbon dioxide in the ocean affects sharks
4.What does the underlined sentence in the last paragraph suggest?
A. Sharks like the squid-scented stream better.
B. Sharks like the stream with the high level of carbon dioxide.
C. Sharks spent 15% of their time in the squid-scented stream.
D. The high level of carbon dioxide can affect the sharks ability to smell.
