Substitute into single word: One living at the same with another

Rewrite the following sentences using right form of verbs.

The girl (play) since afternoon.

Translate into Bangla: 

Water is an important element of the environment. It is essential for the lives of human, animal and plant. Although pure water is safe for us, contaminated water is harmful for our health. Water can be contaminated in various ways. We can get sick by drinking contaminated water.

Fill in the gap with appropriate preposition:

The store is over ____ the lake.

Change the voice of the following sentences:

Whom is he teaching English?

Complete the following sentences with appropriate prepositions:

Suddenly he bursts ____ tears.