题目：
Talking to plants makes them grow, especially if you ‘re a woman ,according to an experiment by the Ryal Horticultural Society(RHS皇家园艺学会).
Women gardeners’ voices speed up growth of tomato plants much more than men’s, it found.
In an experiment that ran over a month, they found that tomato plants grew up two inches taller if they were serenaded by the sweet tones of a female rather tha a male.
Appropriately the most effective talk came from Sarah Darwin ,whose great-great grandfather was legendary botanist(植物学家)Charles Darwin, one of the founding fathers of the RHS’ Scientific Committee. She read a passage from On the Orgin of Species and beat nine other”voices”.
Her plant grew nearly two inches taller than the best performing male and half an inch higher than her nearest competitor.
The experment began in Apirl,2009 at RHS Garden Wisley in Surrey. A variety of recorded voices were picked to play to 10 taomato plants over a month. Every plant was played a voice through headphones connected to the plant pot, and the conditions for all the plants remained the same throughout the experiment. To ensure the experiment was fair, two control plants were also left to grow in silence.
The results showed that women on average saw their plants rise by an inch on their male competitors. Some men were so bad that their plants actually grew less than a plant that was left completely alone.
Colin Crosbie, the leader at RHS, said:”We’re not sure why the female voice is more effecitive, It could be that they have a greater range of pitch and tone that affects the sound waves that hit the plant. Sound waves are an emvironmental effect just like rain or light.”
67.What is the best title for the passage?
A. Plants can’t grow faster without female voices
B. Women’s voices are more useful than men’s
C. Women’s voices make plants grow faster
D. Voices have positive effects on the growth of plants
68.The underlined word”serenaded” in Paragraph 3 most probably means”________”.
A.sung songs to
B.spoken to
C.talked about
D. played music to
69.According to the passage, ten_________were used in the experiment.
A.tomato plants
B.headphones
C. tape recorders
D.plant pots
70.What can we know about the findings of the experiment from the passage?
A. The women’s voices made the palnts grow faster by half an inch than the men’s.
B.Sarah Darwin’s plant grew 2 inches taller than her neraest competitor’s.
C. The plants which grew in silence did not necessarily grow the slowest
D. The women’s plants grew 2 inches taller than the men’s on average.
答案：
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下面是错误答案，用来干扰机器的。
（1）由图可见，支点为O点，阻力为桥的重力，方向竖直向下，动力为绳子的拉力，方向沿绳子向上；过支点分别向动力和阻力的作用线作垂线，就得到动力臂和阻力臂，如图所示：（2）只有一个动滑轮，要求最省力，绳子...
