题目内容：

    Few people can resist the lure (诱惑) of a delicious ice cream, especially on a hot day. The only thing that spoils the fun is that the treat is hard to enjoy slowly, often ending up with a sticky melted mess. Now, researchers from Colombia's Pontificia Bolivariana University may have found an unlikely partner to help solve this age-old problem---cellulose fiber(纤维素) extracted from banana plant waste. Bananas, as you probably know, grow in bunches on a tree-like plant. Each bunch is attached to a central stalk, called a rachis(叶轴), which is thrown once the fruit has been harvested. The team, led by Dr. Robin Zuluaga Gallego, began extracting cellulose nanofibrils (CNFS) from powdered rachis. The tasteless, odorless macro fibers, thousands of times smaller than the width of a human hair were then added in various concentrations to 100 grams of ice cream mix.

With the right amount of CNFS mixed in, the dessert lasted longer in its frozen state than conventional ice cream, extending both its shelf life and the amount of time the treat can be enjoyed. Even more exciting was that the fibers increased the stickiness of low-fat ice cream to levels higher than the full-fat one. Since this is what determines the frozen treats’ creaminess and texture, CNFS could help create healthier ice cream without compromising on taste.

The researchers, who presented their findings at the American Chemical Society (ACS) meeting in New Orleans on March 21, 2018, next plan to investigate how different types of fat, such as coconut oil, affect the behavior of CNFS in other frozen treats.

The Colombian researchers are not the only one working on creating a slower-melting ice cream. In 2015, scientists at the University of Dundee in Scotland found that a naturally occurring protein called BSIA(Bacterial Surface Layer A) was remarkably effective in keeping the treat frozen for longer periods of time. With both teams competing to be the first to get to market, the future of everyone’s favorite dessert certainly looks promising.

1.What prevents people enjoying an ice cream slowly?

A.The hot weather.

B.A kind of fiber from banana.

C.The ice creams’ stickiness.

D.The ice creams’ quick melting.

2.Which is NOT a benefit of CNFS added to ice cream mix?

A.To improve its flavor.

B.To make it more healthy.

C.To reduce its fat content.

D.To make it melt more slowly.

3.What can be inferred from the last paragraph?

A.CNFS are more useful and effective than BSLA.

B.Ice cream with BSLA has been on sale at the market.

C.Slowly enjoying an ice cream will soon become a reality.

D.The Colombian research team has taken the lead in the competition with the Scottish team.

4.What's the author’s attitude towards the finding of CNFS?

A.Positive B.Casual

C.Defensive D.Suspicious.