He admits that he is bad at athletics.

Octans is one of the constellations in the southern hemisphere.

He felt cognitive dissonance between his actions and beliefs.

This model of the cubohemioctahedron is very beautiful, isn't it?

He is working round the clock.

I'm going shopping because I'm out of soy sauce.

He was playing alone in the park.

Looking up at the Big Dipper, I feel at peace.

He is an expert in nuclear physics.

He has already finished writing the report, so we use the present perfect form.