Question

a new use for old clothes
imagine a shirt pocket with the ability to generate enough electricity to recharge an ipod thats carried inside it. while the notion might seem unlikely, scientists have in fact found a way to generate electricity. they simply use fabric with tiny wires woven inside it. scientists havent made any electricity - producing clothing yet, however, the research has been successful thus far: it has raised the prospect of clothing someday possessing the ability to generate power - simply by being stretched or moved.
the research is being led by dr. zhong lin wang. he and his team work at the georgia institute of technology in atlanta, georgia. they used nanotechnology, combined with a principle known as the piezoelectric effect. this occurs when pressure is applied to certain materials, creating electricity. the piezoelectric effect has been understood at least as far back as the 18th century. scientists are now revisiting it with a new level of enthusiasm. they believe it could become an alternative power source. they think it may help address the worldwide energy crisis.
in their experiments, dr. wang and his team layered individual fibers of fabric with minute nanowires made of zinc oxide. these wires are only 30 nanometers in diameter. that is 1,800 times thinner than a human hair. alternating fibers of fabric were then coated with gold. as the fabric was handled, the zinc oxide nanowires
question 4
what is this article mainly about?
a. how nanotechnology has become a widely used alternate power source
b. how dr. wangs team is devising a method to predict nanowires
c. how zinc oxide wires are 1,800 times thinner than a human hair
d. how scientists are using cloth fibers and metals to generate electricity

Explanation:

The article begins by imagining a shirt pocket generating electricity, then details scientists using cloth (fabric) fibers (like those with tiny wires) and metals (such as zinc oxide wires coated with gold) to generate electricity through the piezoelectric effect. Option A is too broad as it says nanotechnology is "widely used" which isn't stated. Option B only focuses on Dr. Wang's team devising a method (too narrow). Option C is just a detail about the wires. Option D概括了文章核心内容 - 科学家如何用布料纤维和金属发电.

Answer:

D. How scientists are using cloth fibers and metals to generate electricity