He continued his strenuous efforts to pass the exam.

He made strenuous efforts to pass the exam.

This medicine contains strychnine.

Free radicals play an important role in chemical reactions.

He called the novel a work of effort.

Understanding dynamical systems is an important part of physics.

He drew his own original character and shared it on social media.

We have to pay property tax every year.

He likes to take a walk in the park at dusk.

Kinetics is the study of the motion of objects.