题目

如图所示，F1代表凸透镜的两个焦点，F2代表凹透镜的两个焦点，请画出光线从凸透镜的左侧焦点射向凸透镜折射后，再射向凹透镜折射后的光路图。 答案：解：如图所示：9. Climate change is an opportunity to unite. The age of competition is of the past;the age of cooperation is      (dawn) ！