题目

Easy Ways to Keep Your Brain Sharp Everyone is forgetful, but as we age, we start to feel like our brains are slowing down a bit — and that can be a very annoying thing.   36   Read on for some techniques worth trying. 1.   37    People who regularly made plans and looked forward to upcoming events had a 50 percent reduced chance of Alzheimer's disease（早老性痴呆症）, according to a recent study.   38   Something as simple as setting a goal to have a weekly coffee date with a friend will do. There’s evidence that people who have a purpose in life or who are wor为了让人们感受丢弃塑料袋对环境造成的影响，某班环保小组的6名同学记录了自己家中一周内丢弃塑料袋的数量，结果如下：（单位：个）33  25  28  26  25  31如果该班有45名学生，那么根据提供的数据估计本周全班同学各家总共丢弃塑料袋的数量为（　　）A．900个B．1080个C．1260个D．1800个