Subject-Verb Agreement

Front

Injuries to football quarterbacks often (happens, happen).

Back

happen

Front

One of the most serious sports injuries is a concussion.

Back

is

Front

Many young people think nothing of a minor blow to the head.

Back

think

Front

Now scientists understand these injuries much better than before.

Back

understand

Front

On impact, the brain arteries (is, are) constricted.

Back

are

Front

Some athletes suffer a second concussion before healing from the first.

Back

suffer

Front

Several minor concussions often lead to permanent brain damage or even death.

Back

lead

Front

Medical doctors nationwide (wants, want) stricter guidelines for athletes with concussions.

Back

want

Front

An athlete with one or more concussions requires sufficient rest.

Back

requires

Front

Today, nobody in contact sports takes a head injury lightly.

Back

takes