Researchers from the Massachusetts Institute of Technology (MIT) have estimated (估计) that the world may need about 1 billion new homes by 2050. According to a researcher from MIT, if people use wood to make so many homes, more than three times the size of the Amazon rainforest may be cut. The MIT researchers tried to find other materials to take the place of wood to make house parts. And they found recycled plastic could play a role.

The MIT team discovered that recycled plastic mixed with bits of glass could be used as a new material to make trusses (桁架)—supports put under floors to make sure that the floors can carry the weight of everything on them.

The MIT team wanted to know how much weight the trusses could carry. In a test, they 3D printed four trusses with the new material. Each truss weighed only about 6 kg—lighter than a comparable wooden truss. The team put the four trusses under a wooden floor model and slowly added heavy weights on the floor. Through the test, the team found the four trusses could sustain objects weighing more than 1,800 kg—about the weight of a car. This showed trusses made from the new material were strong enough to be used in house building in America.

The finding may benefit house building a lot. It will be much easier to send house parts made from this new material to different places. What’s more, the researchers say it is possible to bring down the cost of making house parts. The researchers hope that one day they can 3D print more house parts with the new material, so that more used plastic could be turned into something useful.

1.1.How many new homes may the world need by 2050 according to the MIT researchers?

A About 1 billion.

B About 2 billion.

C About 3 billion.

D

解析：选A。A 细节理解题。原文第一段：the world may need about 1 billion new homes by 2050. 原文直接给出数据，约 10 亿套新房。

2.2.What is the new material made from?

A Recycled plastic and glass.

B Recycled plastic and wood.

C Recycled plastic and stone.

D

解析：选A。A 细节理解题。原文第二段：The MIT team discovered that recycled plastic mixed with bits of glass could be used as a new material.新材料由再生塑料 + 玻璃碎屑混合而成。

3.3.What does the underlined word “sustain” probably mean in Paragraph 3?

A Increase.

B Avoid.

C Hold.

D

解析：选C。C 词义猜测题。文中指桁架可以承受、支撑1800 千克重物。increase 增加；avoid 避免；hold 承受，支撑。

4.4.What can we learn about the 3D-printed trusses in the test?

A They were big enough to support house floors.

B They were strong enough for house building.

C They were small enough to be put in a car.

D

解析：选B。B 细节理解题。原文第三段：This showed trusses made from the new material were strong enough to be used in house building in America.实验证明桁架强度足够用于建房。A（足够大）文中未提；C（小到可以放进车里）曲解原文，重物重量等于一辆车，不是桁架放进车里。

5.5.Which of the following is the best title for the text?

A 3D Printing Solves Housing Problems.

B Recycled Plastic Finds New Life in Houses.

C Recycling Plastic Reduces Environmental Pollution.

D

解析：选B。B 主旨大意题。文章核心：再生塑料被做成房屋建材。A选项3D打印只是制作手段，不是主旨；C选项偏离文章重点。不是减少污染，而是塑料用作建房材料。