题目

已知是平行六面体．设是底面的中心，， 设，则的值为___▲_______． 答案：  任务型阅读请认真阅读下面的材料，按要求完成信息表。合理的饮食与我们的健康密切相关。Coco, Dan, Marc, Sally和Wang Hai对食物有各自不同的喜好。请从A-E中选出符合个人情况的图片。【1】Coco eats a lot of fresh fruit and vegetables. She thinks they’re healthy and they taste good. She doesn’t love sweet things and she doesn’t eat much fatty food.【2】Dan loves sweet things like cakes and chocolates. He knows this kind of food isn’t good for him, but he can’t give them up.【3】Marc says, “ I’m afraid I love junk food—You know, quick, unhealthy food like hamburgers or chips. A lot of people think it not good, but I like it. I don’t eat many fresh vegetables.”【4】 Sally says, “Crisps* are my favorite. I know they’re bad for me, but they are delicious, especially cheese and onion ones.”【5】 Wang Hai is a Chinese boy. He used to eat too much meat and became fat. Now he follows a doctor’s advice to eat rice and many vegetables with less meat. “I’m no longer fat, and I must keep healthy,” he said.ABCDE