Quinine is used for the treatment of malaria.

He is my greatest opponent.

He has been a stamp collector since long ago.

Keith is my best friend.

Our family has become multicultural through intermarriage.

Our families have been intermarrying for a long time.

He set up the detonator.

He detonated the bomb.

He lectured to the students.

I will attend the lecture held at the university today.