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A．Newton's life and times.B．The influence of earlier scientists on Newton's ideas.C．Ho
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听力原文：On Monday we talked about insects, and how they gather food. Today I'd like to talk about the common garden spider and how it captures its prey with net-like structure it first produced almost 200 million years ago. I mean, of course a spider web. What's interesting is why such a delicate structure isn't hard. When a fast-flying insect crashes into it, and compared with the spider, these insects can be huge and really heavy. In fact capturing a large insect in a spider web could be compared to capture an airplane in a fishing net. So, how can the web offset such a shock without breaking？ is it just because the thread is made of so strong？ well, experts analyze spider webs using a computer program designed when an insect crashed and caught and they found the structure of the web, the way of threads connected together helps balance the strength and tensions caused by the impact and spread them all across the web this saves the web from being destroyed and by the way, suggests some creative new ideas that human might use in designing buildings. The biggest surprise, though, is the role of air resistance in cushioning the shock of collision. The computer model showed that dragging a tightening thread from a spider web through the air is a lot like pulling a heavy rope through water. And since air resistance acts on many threads all across the web its amazing effect that multiplies many times. And this definitely helps the web survive the impact
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A．Chemists.B．Architects.C．Airline pilots.D．Auto designers.
Compared to the tail of electrically charged atoms, the tail of neutral dust particles is
A．They're much larger than spiders.B．They're quite delicate.C．They have unusual ways o
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