In order to keep the balance of ecosystem, every possible means _______to deal with the problems of the over-exploiting of natural resources. 

The pen my father sent me as my birthday gift           very well.

Had it been possible I would have gone to the movies, but I ________________ busy.

Cole Bettles ______ by a number of universities when he received an e-mail from the University of California last month. 

I must be off now. My friends ________ outside.