This exam is a matter of life or death for me.

He is viewing that situation as a serious problem.

He views that situation as a problem.

A new approach is needed to solve this set of problems.

The main problem with this project is the lack of communication.

This question text is too difficult, it's hard to understand.

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

The human immunodeficiency virus destroys the immune system, causing the body to lose its ability to fight disease.

The human immunodeficiency virus is the virus that causes AIDS.

The feline immunodeficiency virus can potentially have serious effects on a cat's health.