题目内容：

    Whether paired with a bottle of nice red wine or a burger, cheese can be a delicious treat. But it is not perhaps, the ideal material to use in printing — unless you are a team of nutritional scientists. One group of researchers used 3D printing to create a cheese. And the cheese could provide a valuable insight for engineers who are still developing materials for 3D printing.

A team from the school of food and nutritional sciences at University College Cork (UCC) conducted a series of tests evaluating the 3D-printed cheese. 3D printing materials need to be fluid (液态) enough to flow but also capable of setting into a definite shape or structure.

After melting the cheese at 75°C (167°F) for 12 minutes, the UCC team then ran it through a modified commercial 3D printer. The machine, which usually prints with plastic, was fitted with a syringe (注射器) to allow it to print with the melted cheese.

The UCC team used several techniques to examine the effects of the 3D printing process on their cheese. They compared the 3D-printed results to processed cheese that had been melted and then cooled, as well as another sample that was left untouched. Cheese that was 3D printed was 45% to 49% softer than the processed cheese, the researchers said. They also discovered that 3D-printed cheese was a little darker in colour and more fluid when melted, though it melted at about the same temperature as processed cheese.

Dr Kelly and his colleagues are now testing other types of dairy products which can be 3D-printed. Dr Kelly said, “We are using mixtures of milk proteins at present to build a product, perhaps a high-protein snack, and designing recipes which might work best for a 3D printer. ”

1.What problems are the engineers facing in 3D printing a cheese?

A.They don't have proper material.

B.They can't find a bottle of nice red wine or a burger.

C.They can't make the cheese very delicious.

D.They know much less than nutritional scientists.

2.How did the researchers use the 3D printer to make cheese?

A.They raised the temperature to 75°C.

B.They added a syringe to the printer.

C.They bought some cheese to paint it.

D.They evaluated the 3D-printed cheese.

3.What is the advantage of the 3D-printed cheese?

A.It melts more easily. B.It tastes more delicious.

C.It costs less money. D.It is much softer.

4.What will Dr Kelly and his colleagues do next according to the last paragraph?

A.Publish a report on their research.

B.Invent a new 3D printer.

C.3D print more milk food.

D.Make more cheese with their machine.