More and more people were gathering there. He ________ his way through the crowed and rushed into the burning house.

The air ______ different gases _____ together.

His book, which _______ last week, should be another best-seller. 

Affected by the financial crisis, Jack's business is not as good as before, so he has to ________ the expenses of his company.

In order to ______ his muscle, Mike goes to the gym regularly to do exercise.