Answer:
The correct form of the verbs to indicate that it was in progress at a time in the past is:
- <u><em>estaban</em></u><em> - </em><u><em>esperando</em></u>.
<em>- </em><em>Ellos </em><em><u>estaban esperando</u></em><em> en la fila.</em>
Explanation:
The translation of the sentence is:
- They <u>were waiting</u> in line.
The time that mentions the actions that are carried out at a certain moment is the progressive time or continuous time, which is characterized by two things:
1. The use of the verb <em>"estar"</em> in the respectively tense:
- Present: <em>estoy, estás, está, estamos, están</em>.
- Past: <em>estaba, estabas, estábamos, estaban</em>.
2. The conjugate verb ends in <em>"ando"</em> or <em>"endo."</em>
Below are the different conjugations of the verb <em>"estar"</em> in Past Tense depending on the personal pronoun:
- <em>Yo </em><em>estaba.</em>
- <em>Tú </em><em>estabas.</em>
- <em>Usted </em><em>estaba.</em>
- <em>Él </em><em>estaba.</em>
- <em>Ella </em><em>estaba.</em>
- <em>Ello </em><em>estaba.</em>
- <em>Nosotros/Nosotras </em><em>estábamos.</em>
- <em>Ustedes </em><em>estaban.</em>
- <em>Ellos/Ellas </em><em><u>estaban</u></em><em>.</em>