Question

Which of the following sentences contains a helping verb?

We should stop and ask for directions.

The plane departed for Dallas an hour late.

I spoke with my friend yesterday evening.

Tanya forgot to bring her lunch today.

Answer 1

The sentence that contains a helping/auxiliary verb is the first one - We should stop and ask for directions.
The helping verb there is should. Helping verbs are used to form complex tenses, such as present continuous, or future perfect, etc.