so much to our diet，” says Dr.

　　Jeff Pettis of the Bee Research Laboratory.

　　California's almond crop alone depends on about half the bees in the country. But now the almond crop and many others could be in trouble with so many bees dying.

　　Researchers at government and university labs all over the country are trying to figure out why so many bees are dying. However, bees are hard to study. Most die away from the hive, so researchers don't have dead bodies to examine. And when researchers return to a hive after two weeks, about half the bees they studied on their first visit will be dead, replaced by new ones in the natural life cycle of bees. “It isn't like studying a large animal like a cow that doesn't move around much and is easy to find out in the cow field，” says Pettis.

　　Researchers have some ideas about what could be affecting bees' health. They could be sick because of poisons widely used to kill insects, or they might not be getting enough good food to stay strong. Also, tiny insects called mites feed on bees. “A virus or bacteria could also be doing the killing，” explains Pettis.

　　蜜蜂除了提供蜂蜜之外，还帮助植物授粉，它们是人类的益友。但加利福尼亚的大量蜜蜂出现了不明原因的死亡，这引起了人们对重要粮食作物的担忧。

　　4．What is Paragraph 2 mainly about?

　　A. The wind helps pollinate.

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