Over the past decades, the population in this country because of the rising birth rate, immigration and the declining death rate.

We should balance our work and relaxation, and only by doing that, as everybody would agree, ____ a good state of mind. [ ]

Preparations have been ______for the project and it can be started at any moment.

The subjects we have at school_____biology.

Is there anyone in the classroom?—No, not only the students but also the teacher　　　　to watch the opening ceremony of the Asian Beach Games.