What is he doing when it is raining?(划线部分是reading)
Who is reading when it is raining?(划线部分是he)
When is he reading?(划线部分是it is raining)
What is he doing when it is raining?(划线部分是reading)
Who is reading when it is raining?(划线部分是he)
When is he reading?(划线部分是it is raining)