SSS 2012-01-18
时间：2019-01-08 作者：英语课 分类：Scientific American(一)月
True to their names, boa constrictors squeeze the life out of their prey 1. But how dose a boa know it’s enough for a rat? The snake listens, for a heart beat. When it stops, that’s a cue to let go, according to a study in the Journal biology letters. Researchers outfitted 2 with artificial beating hearts. They used dead rats to control for other signs of , like muscle. Then they warmed up the rats, set the hearts pumping and dangled 3 them in front of hungry Boas. The sankes attacked, and as long as that rat heart pumping, the boas kept tightening 4 their coils and p of pressure, sometimes for more than 20 minutes. But as soon as the scientists kill the heart beat, the boas loosened up. Even captive boas, who had never hunted a live prey paid attention to the pulse, suggesting the behavior is innate 5 and for good reason. The authors say constricion takes a lot of energy, and it can be dangerous, say, if an enemy strikes while the snake’s coiled around its . But by following heart, boas can keep the pressure on just long enough before a relaxing meal.
- Stronger animals prey on weaker ones.弱肉强食。
- The lion was hunting for its prey.狮子在寻找猎物。
- They outfitted for the long journey. 他们为远途旅行准备装束。 来自《现代英汉综合大词典》
- They outfitted him with artificial legs. 他们为他安了假腿。 来自辞典例句
- Gold charms dangled from her bracelet. 她的手镯上挂着许多金饰物。
- It's the biggest financial incentive ever dangled before British footballers. 这是历来对英国足球运动员的最大经济诱惑。
- Make sure the washer is firmly seated before tightening the pipe. 旋紧水管之前，检查一下洗衣机是否已牢牢地固定在底座上了。
- It needs tightening up a little. 它还需要再收紧些。
