This room is always kept clean.

He is always facing difficulties, just like the proverb 'clouds over the moon, wind in the flowers'.

Essential fatty acids are vital nutrients for our health.

Essential amino acids cannot be produced by the human body, so they need to be obtained from the diet.

Surface meteorology is a part of meteorology that studies the interaction between the surface and the atmosphere.

He built up wealth.

His lifework is teaching music to local children.

The company suffered from damage caused by unfounded rumors.

The atmosphere of the meeting has grown tense.

He and I are related by blood.