如图a,小华用20N的力拉着行李箱行走,拉力的方向与水平面成30°.请在b图中画出行李箱所受拉力的示意图.
解:如图所示:
下列说法或做法与生态农业的设计思路不符的是( )
世界上的发达国家(美、加、英、法、德、意、日等)主要分布在( )
Another new year is coming. It's up to all of us to fill it with things____ promise progress and happiness.