What’s the matter with the little boy?—A bad traffic accident happened _____ him. What a pity![ ]

I think swimming is ______ hiking. [ ]

__________ good grades, you should try to study harder.

We will go to Shanghai ______ the evening ______ May 2rd.[]

____ in Jiangxi Province the next morning _____ we found many places flooded by the thunderstorm.