Oxygen, which is one of the chemical elements, is necessary for us to breathe.

The mischievous child messed up the neighborhood flower bed.

He always has a mischievous smile on his face.

My grandmother's forty-ninth day is next week.

My grandmother's forty-ninth day is next week.

He learned the movements of the solar system using an orrery.

She likes to dance at the club every weekend.

He was standing at the summit of the mountain.

We conducted a detailed investigation into the issue.

He is working at that ministry and agency.