题目内容：

    Few people can refuse a delicious ice cream, especially on a hot day. The only thing that stops the fun is that the treat is hard to enjoy slowly, ending up with a sticky, melted mess. Now, researchers from Colombia’s Pontifical Bolivarian University may have found an unlikely thing to help solve this age-old problem — a kind of fibre from banana plant waste.

Bananas, as you probably know, grow in groups on a tree-like plant. Each group is connected to a central rachis (叶轴), which is thrown once the fruit has been gathered. The team, which was led by Dr. Robin Zuluaga Gallego, began by abstracting /drawing out cellulose nanofibrils (CNFs) from the powdered rachis. The tasteless fiber, thousands of times smaller than the width of a human hair, was then added to 100 grams of ice cream mix.

With the right amount of CNFs mixed in, the dessert lasted longer in its frozen state than the traditional ice cream, extending the amount of time that the treat can be enjoyed. What was even more exciting was that the fibre increased the stickiness of the low-fat ice cream to levels higher than the full-fat one. Since this is what determines the frozen treat’s creaminess and taste, CNFs could help create the healthier ice cream without influencing the taste of it.

The researchers, who presented their findings at the American Chemical Society( ACS) meeting in New Orleans in March, 2018, next plan to study how different types of fat, such as coconut oil, influence the behaviour of CNFs in other frozen treats.

The Colombian researchers are not the only ones working on creating a slower-melting ice cream. In 2015, scientists at the University of Dundee in Scotland found that a natural protein called BsIA was very effective in keeping the treat frozen for longer periods of time. With both teams fighting to be the first to get to the market, the future of everyone’s favorite dessert certainly looks bright.

1.What prevents people enjoying an ice cream slowly?

A.A kind of fibre from bananas.

B.The ice cream’s quick melting.

C.The ice cream’s stickiness.

D.The fat in the ice cream.

2.Why were CNFs added to ice cream mix?

A.To improve its taste.

B.To increase its stickiness.

C.To reduce its fat content.

D.To make it melt more slowly.

3.What does the underlined word “it” in Paragraph 3 refer to?

A.The ice cream. B.The fiber.

C.The fat. D.The stickiness.

4.What can be inferred from the last paragraph?

A.BsIA is popular in the market.

B.CNFs are more useful and expensive than BsIA.

C.Ice creams with CNFs have been on sale at the market.

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