下列说法中正确的是（ ）
A．乐音就是乐器发出的声音，它不可能是噪声
B．打开门窗，加快空气的流动，可以减弱马路上的噪声
C．噪声可以影响人们的休息和学习，但不会影响健康
D．植树造林可以保护环境，减弱噪音
A、从环保的角度说，凡是影响人们正常工作或休息等的声音，都属于噪声，因此乐音有时候也可能是噪声．故本选项说法错误．
B、打开门窗，加快空气的流动，但不可以减弱马路上的噪声；故本选项说法错误．
C、噪声可以影响人们的休息和学习，同样会影响健康；故本选项说法错误．
D、植树造林可以在传播过程中减弱噪声，因此在马路边种植花草树木可以减弱噪声，故本选项说法正确．
故选D．
| 完形填空。 | ||||
| Who designed (设计) the first helicopter (直升飞机)? Who 1 of the most famous pictures in the world? Who knew more about the human body than most 2 ? There is an answer 3 all. these questions -Leonardo de Vinci (达·芬奇). Leonardo may have been the greatest genius (天才) 4 have ever known. He lived in Italy around the year 1500, but many of his inventions seem modern to us today. For example, one of his notebooks has drawings of a helicopter. Of course, he couldn't 5 a helicopter with the things he had. But scientists say his idea would have worked. But Leonardo 6 an inventor. He was one of the greatest artists of his day. By the time he was twenty years old, he was called a master (大师) painter, and as he got older he became 7 more famous. Sometimes he drew a hand ten different ways 8 he was ready to paint. Many of Leonardo's wonderful paintings are still with 9 today. You may know one of his most famous works the 10 woman known as the Mona Lisa. | ||||
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