A：ee
B：ea
C：ei
____
- The population of China is larger than ______ of India.
- Yes, but India's population is increasing rapidly.
小军同学利用焦距为15cm的凸透镜做了“探究凸透镜成像规律”的实验，实验中当光屏距凸透镜18cm时，会在光屏上出现一个____（选填“缩小”、“等大”或“放大”）的实像．应用这一成像原理制成的光学仪器是____（答出一个即可）．
