She used to be a prostitute, but now she has started a new life.

Will you marry me?

"Do you want to have a meal? Take a bath? Or choose me?" she said jokingly.

He was hiding the fact that he was an illegitimate child.

Masato is my best friend.

A tautology refers to a logical formula that is always true, no matter what values are substituted.

The sphericity of this object is very high.