Mr. White lives in the countryside with his wife, Mrs. White. From Monday to Friday he works in a small office near his house. He is free on Saturdays and Sundays. He has a nice garden near his house. He likes growing flowers and he usually works in the garden on Saturdays and Sundays. The flowers are colourful and beautiful. Mrs. White likes them very much. She often helps Mr. White. They live happily together.

读四省区轮廓图，完成下列要求：

下列实验操作错误的是（  ）

如果一束平行光经过眼睛的角膜和晶状体折射后所成的像落在视网膜____（选填“前”或“后”），这就是近视眼，需要佩戴____镜矫正。