Subject-verb agreement

In English, a third-person singluar subject requires a verb form with an -s (in the present tense). Errors of agreement (also known as concord) sound particularly bad to native speakers.

Poverty affect us all in one way or another.

Poverty affects us all in one way or another.

In what ways are racism reproduced through language?

In what ways is racism reproduced through language?

By the same token, do not put an -s on a verb when the subject is not third-person singular.

The environment and people around us affects us more than we might think.

The environment and the people around us affect us more than we might think.

Many people thinks this is simple.

Many people think this is simple.