题目

阅读理解 An apple a day keeps thedoctor away is one of the most common sayings in the English languages.This is because apples were one of the first foods that medical professionalsrecognized as healthy­their benefits became obvious whenquite simply, doctors found that people who ate apples were sick less often than those who did not. Today we have a more specific understanding of why apples are so beneficial to overall health.Apples can help keep your levels of bad cholesterol (胆固醇) down. The pectin (果胶) in apples helps you to maintain cardiovascular health and reduce LDL chole10．如图，画出被投出去的篮球的受力示意图（不计空气阻力和浮力）．