Convenient ___private cars are for us, they may also cause traffic accidents and pollution.

__________ is responsible for the Chenzhou train collision will be punished.  

(2013·青岛一模)You seem to have a ready­made answer ________ I ask you a question.

My sister was angry ______ what he said.

On June 16, 2012, it arrested the world’s attention ______ Shenzhou9 spacecraft was successfully sent into the sky with the first Chinese woman astronaut.