He tried to change history by using a time leap to go back to the past.

He was half dead from fatigue.

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 diagonal elements of this matrix are all 1.

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.