A．He ate a lot of food poor in calories.

　　B．He believed potato chips were healthy food.

　　C．He thought each serving had few calories.

　　D．He mistook calories of per serving for each bag's.

　　4．What's the main idea of the passage?

　　A．Goods on sale are usually bad.

　　B．Ads today are hard to understand.

　　C．Buyers should beware of marketing tricks.

　　D．Forgetting the calories makes life easier.

　　B

　　Songs that make our hearts happy can make them stronger too, US researchers reported on Tuesday.

　　They found that when people listened to their favorite music, their blood vessels (血管) dilated in much the same way as when they are laughing, or taking blood medications.

　　"They have a pretty impressive effect，" said Dr Michael Miller, director of preventive cardiology (心脏病学) at the University of Maryland Medical Center in Balitimore.

　　"Blood vessel diameter improved，" he said."The vessel opened up pretty significantly. You can see the vessels opening up with other activities such as exercise." A similar effect is seen with drugs such as statins.

　　When blood vessels open up more, blood flows more smoothly and is less likely to form the clots (凝块) that cause heart attacks and strokes."We are not saying to stop your statins or not to exercise but rather to add this to an overall program of heart health，" said Miller, who presented his findings to a meeting of the American Heart Association in New Orleans.

　　Miller's team tested 10 healthy, non­smoking men and women, who were told to bring their favorite music. They spent half an hour listening to the recordings and half an hour listening to music they said made them feel anxious while the researchers did ultrasound (超声波) tests designed to show blood vessel function.

　　Compared to their normal baseline measurements, blood vessel diameter increased 26 percent on average when the volunteers listened to their joyful music. Listening to music they disliked, blood vessels narrowed by six percent, Miller said.

Miller said he came up with the idea after discovering that laughter caused blood to literally flow more smoothly."I asked myself what other things make us feel good, besides calories from