Chemical pollution has a serious impact on the health of the Earth.

He negotiated with his boss for a raise in salary.

He is hoping that his salary will be increased.

He is asking for a reduction in taxes.

He is thinking of tax-saving measures to reduce his taxes.

The school rules of this school are strict.

Photochemistry is a branch of chemistry that studies chemical reactions affected by light.

Photochemistry is a branch of science that studies how chemical reactions proceed under the influence of light.

I used the student discount at the movie theater.

Paleoecology is a field of study that investigates the relationship between past organisms and their environment.