He always boasts, but in reality, he does nothing.

He has a habit of always boasting.

A skew-symmetric matrix has the characteristic that its transpose matrix is the inverse of the original matrix.

A diagonal matrix is a matrix in which all elements outside the main diagonal are zero.

The police apprehended the criminal.

He is the leader of that team.

The signal from the cell phone relay-station in this area is weak.

I create a balance sheet every month to understand my financial situation.

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.

The 正六百胞體 is one of the regular polytopes in four dimensions.