In chemistry class, I learned about acidic oxides.

Bioweapons are a major threat to humanity.

In this experiment, we will observe the reaction of organic compounds.

In this experiment, we will use various inorganic compounds.

Tanzan is my best friend.

He is looking for something.

Every morning, when dawn breaks, I go for a walk.

Let's go up the stairs one step at a time.

He started a fire using coal.

His answer was short.