The umpire declared a balk on the pitcher.

Mr. Zhai is my best friend.

This ancient proverb, 'know the other side and yourself, and you will not be in danger in a hundred battles', teaches us the importance of understanding ourselves and others.

He checked whether he remembered or not.

The ship sank into the sea.

My mother woke me up.

My new keyboard makes typing very enjoyable.

I play volleyball with my friends every weekend.

The motherboard of my computer has broken.

Seaborgium is one of the elements on the periodic table.