He is working hard to pay off his debts.

This material has the ability to absorb the heat of the sun.

This chemical reaction is an endothermic reaction.

Vaccination against classical swine fever is very important for maintaining the health of pigs.

Thermonuclear reactions are the source of the sun's energy.

This house is built using insulation materials.

He understands the basic concepts of thermodynamics.

He prayed earnestly for his sick mother.

He prayed fervently for his sick friend.

When the volcano erupted, a glowing cloud covered the sky.