Day after day, he continued to strive to solve the problem.

My younger sister is twenty-two years old.

It takes twenty minutes to get to my house.

He had twenty old coins.

It takes twenty minutes to get to my house.

There are twelve students in my class.

The thirty-first day is my birthday.

The new project will start in seventy-five days.

Today is my birthday, a very lucky day.

Today is my birthday.