It's difficult to decipher this chemical equation.

Understanding chemical equations is difficult.

We are growing vegetables without using chemical fertilizers.

Oxygen, which is one of the chemical elements, is necessary for us to breathe.

Understanding chemical equilibrium is very important in understanding chemical reactions.

This substance undergoes a chemical change when heat is applied.

In this experiment, you can observe a chemical reaction.

My child attends a supplementary school every Saturday.

He understands the meaning of the proverb 'Teaching is half learning', which means that teaching leads to one's own learning.

He delivered the news with a shameless smile.