He was enjoying a schuss on his skis.

He schussed down the mountain on skis.

This rock contains pyrite.

These vectors are orthogonal.

These lines intersect orthogonally.

He provided a detailed explanation to elucidate the issue.

I spent the summer vacation with my relatives.

The calculation of integrals is an important part of mathematics.

There are many ancient stone Buddhist images in this park.

Who is the person in charge of the project?