This plant needs sufficient exposure to light.

He exposed the solar cells to sunlight to charge them.

She made a bowstring using horsehair.

Mr. Sone is my best friend.

This rock is gabbro.

He cleaned the bowl of the pipe thoroughly.

The students lined up in response to the teacher's instructions.

He is majoring in petrology at university.

This cigarette contains carcinogens.

I used binoculars to observe birds in the mountains.