The little girl was jumping __________ in the kindergarten, waiting for her mother.

—It’s too hot. ---Let’s open the windows to allow the air to_________.

People’s working efficiency usually decreases more or less when the temperature _________ 35℃ or even higher. 

Car dealers also have a tough time in bad economy. Therefore，they have to ________ their business model to overcome the difficulties.

We ________ go out when it rained.