题目

阅读下面短文，根据其内容写一篇60词左右的内容概要。TakeCare of Your Spine (脊柱)The spine stands at thecenter of your health, providing your body with structure and support. It alsocontains your spinal cord, a massive collection of nerves that sends electricsignals from the rest of your body to your brain. Therefore, it's important totake care of it. Maintaining your good postureis one of the most important things you can do to keep your spine healthy.Proper posture means standing or sitting while keeping your spine straight,except for its natural curves. Posture comes四边形ABCD中，若∠DAC=∠BCA，∠DCA=∠BAC，且∠D=52°，则∠B= ．