He was behaving as if he was crazy.

He and I compete in tennis every week.

I was amazed at his new idea.

Acoustic phonetics is the study of the physical properties of speech.

The Federal Republic of Yugoslavia was once an existing nation.

Zoonosis refers to diseases that can be transmitted from animals to humans, or vice versa.

Zoonosis is a disease that spreads from animals to humans, or vice versa.

He chose a stable job, saying 'a bird in the hand is worth two in the bush.'

The Democratic Republic of the Congo is located in the central part of the African continent.

He is receiving treatment for obsessive-compulsive disorder.