He prayed fervently for his sick friend.

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

In the midday heat of summer, he continued to work while drenched in sweat.

He said he was feeling feverish and left early.

Please preheat the oven.

His passion for the game flared up again.

His flaring up again means that he is immersing himself in that hobby again.

Thermal pollution can potentially have serious effects on marine life.

Lassa fever is a serious infectious disease that is particularly prevalent in West Africa.

He is studying thermodynamics in depth.