He suddenly developed acute pneumonia.

The educational methods of schools under the old system were significantly different from those of current schools.

She changed her name after getting married, but her maiden name was Tanaka.

He is suffering from a subacute illness.

He has a brash personality and tends to jump to conclusions quickly.

We held a study session at school for the underclassmen.

We were enveloped in deep sorrow due to his sudden death.

He died suddenly at a young age.

This textbook-style font is easy to read, isn't it?

He lent his chest to his friend and listened to his worries.