This problem is very difficult.

He voluntarily took on the job.

We will contact you as soon as we confirm the progress of the construction.

We should go forward.

He has been diagnosed with manic depression and is receiving treatment.

The forest is quiet.

We had a picnic in the forest over the weekend.

The forest is a quiet and beautiful place.

He took an arrow out of the quiver.

I have been studying all the time.