温馨提示：
此套题为Word版，请按住Ctrl,滑动鼠标滚轴，调节合适的观看比例，答案解析附后。关闭Word文档返回原板块。
课时提升作业(二十二)
必修4 Module 4
Ⅰ. 阅读理解
A
Any child who has played with blocks knows why they’re so useful. Kids can build almost anything from them—a plane, a castle, even a race car. And if one part of a creation comes apart or breaks, the builder doesn’t have to start from scratch. He can just replace the missing blocks. And what’s true for kids’ play is also true for adult projects.
Scientists have just created a new type that resembles the letter X. These pieces are small and lightweight yet strong. And they’re inexpensive. One day they may be fixed into bikes, bridges, planes or buildings. Just as with toy blocks, if one piece breaks, engineers can swap it out without scrapping the whole project.
“When you read about this invention, ”Rainer Adelung said, “you think: ‘Why hasn’t anyone done this before?’”
The material used in the new X blocks is often called, simply, a composite. Engineers took carbon fibers, each thinner than a human hair, and wove them into a hard plastic substance.
