He is struggling to understand the perfect tense in English.

She is struggling to understand the perfect tense in English.

His country is facing a crisis of territorial violation.

His country was sued in the International Court of Justice for the crime of violating territorial sovereignty.

Yesterday, our country's airspace was violated by the enemy nation.

North Korea has violated our country's airspace again.

We installed a new flowmeter in the factory.

He exercises his rhomboid muscles at the gym every day.

兩唇音 is a type of sound produced using the lips.

The ritsuryō system was a system that ruled ancient Japanese society.