Are you a____(健康的) child? Bob, a 14-year-old boy, is very unhealthy. He likes to ____ (乘坐) his father's car to school. Sometimes he goes to school by ____(地铁).  He does exercise only ____ ( 一次) a week. He likes eating ____(垃圾) food very much. This week his parents are in Paris on ____ (度假). So he eats lots of unhealthy food every day. Now Bob is badly____(生病的) in hospital. The doctor says, “ You should ____ （经常）do exercise, and have a good ____(饮食) habits. It's ____ (重要的) for your health. 

如图所示，水平地面上放置相同材料制成的四个木块，其中两个质量为m的木块间用一不可伸长的水平轻绳相连，下面两个木块质量分别为2m和3m．现用水平拉力F拉其中一个质量为3m的木块，使四个木块一同水平向右匀速运动，则（　　）

                                                                                                 乡村四月
                                                                                              【宋】 翁卷
                                                                              绿遍山原白满川，子规声里雨如烟。
                                                                              乡村四月闲人少，才了蚕桑又插田。

气体从外界进入人体血液内最合理的路线是（　　）