In this exercise, we need to complete the sentences with the correct verb form of the imperfect or the preterite.
The sentence reads:
*”Students already ____ (work) when their teacher ____ (enter).”*

We use the preterite tense when we are talking about the events and actions that happened only once and were completed in the past.
We use the imperfect form when we are talking about ongoing events in the past, habitual and actions that happened more than once. Also the imperfect is used when we are describing background information, emotions, age, date, weather, etc.

In the sentence where we have two verbs that don’t interrupt each other’s actions, both verbs are in the imperfect tense.
When we have two verbs and the action of the verb in progress was interrupted with other verbs action, the verb in progress goes in the imperfect tense and the other verb in the preterite tense.

The subject of the first verb is *los estudiantes* (the students) and of the other verb is *profesor* (professor).
In the sentence, we have two verbs and the action of the second verb interrupted the action in the progress of the first verb. Therefore, for the first blank we will use the third-person plural imperfect form of the verb *trabajar*(work), which is “trabajaban”.
For the second blank, we will use the third-person singular preterite form of the verb *entrar* (enter), which is “entró”.

trabajaban; entró

In this exercise, we need to complete the sentences with the correct verb form of the imperfect or the preterite.
The sentence reads:
*”The teacher ___ them (say), “you are very hardworking”.”*

We use the preterite tense when we are talking about the events and actions that happened only once and were completed in the past.
We use the imperfect form when we are talking about ongoing events in the past, habitual and actions that happened more than once. Also the imperfect is used when we are describing background information, emotions, age, date, weather, etc.

In the sentence where we have two verbs that don’t interrupt each other’s actions, both verbs are in the imperfect tense.
When we have two verbs and the action of the verb in progress was interrupted with other verbs action, the verb in progress goes in the imperfect tense and the other verb in the preterite tense.

The subject of the verb is *el profesor* (the professor).
In the sentence, we have an action that happened only once, the professor told the students only once that they are hardworking. As we know for the actions that happened only one time in the past we use the preterite tense. Therefore, we will use the third-person singular preterite form of the verb *decir* (tell), which is “dijo”.

dijo

In this exercise, we need to complete the sentences with the correct verb form of the imperfect or the preterite.
The sentence reads:
*”Then the teacher ___ (do) a demonstration of a new art technique.”*

We use the preterite tense when we are talking about the events and actions that happened only once and were completed in the past.
We use the imperfect form when we are talking about ongoing events in the past, habitual and actions that happened more than once. Also the imperfect is used when we are describing background information, emotions, age, date, weather, etc.

In the sentence where we have two verbs that don’t interrupt each other’s actions, both verbs are in the imperfect tense.
When we have two verbs and the action of the verb in progress was interrupted with other verbs action, the verb in progress goes in the imperfect tense and the other verb in the preterite tense.

The subject of the verb is *el profesor* (the professor).
In the sentence, we have an action that happened only once, the professor showed the students the new technique only once. As we know for the actions that happened only one time in the past we use the preterite tense. Therefore, we will use the third-person singular preterite form of the verb *hacer* (do), which is “hizo”.

hizo

In this exercise, we need to complete the sentences with the correct verb form of the imperfect or the preterite.
The sentence reads:
*”While the students (practice), the teacher ____ (walk) around the class to observe their progress.”*

We use the preterite tense when we are talking about the events and actions that happened only once and were completed in the past.
We use the imperfect form when we are talking about ongoing events in the past, habitual and actions that happened more than once. Also the imperfect is used when we are describing background information, emotions, age, date, weather, etc.

In the sentence where we have two verbs that don’t interrupt each other’s actions, both verbs are in the imperfect tense.
When we have two verbs and the action of the verb in progress was interrupted with other verbs action, the verb in progress goes in the imperfect tense and the other verb in the preterite tense.

The subject of the first verb is *los estudiantes* (the students) and of the other verb is *profesor* (professor).
In the sentence, we have two verbs and the actions of the verbs don’t interrupt each other. Therefore, for both verbs, we will use the imperfect tense. For the first blank we will use the third-person plural imperfect form of the verb *practicar* (practice), which is “practicaban”.
For the second blank, we will use the third-person singular imperfect form of the verb *caminar* (walk), which is “caminaba”.

practicaban; caminaba

In this exercise, we need to complete the sentences with the correct verb form of the imperfect or the preterite.
The sentence reads:
*”The teacher ____ (be) happy because his students ___ (learn) the technique very well.”*

We use the preterite tense when we are talking about the events and actions that happened only once and were completed in the past.
We use the imperfect form when we are talking about ongoing events in the past, habitual and actions that happened more than once. Also the imperfect is used when we are describing background information, emotions, age, date, weather, etc.

In the sentence where we have two verbs that don’t interrupt each other’s actions, both verbs are in the imperfect tense.
When we have two verbs and the action of the verb in progress was interrupted with other verbs action, the verb in progress goes in the imperfect tense and the other verb in the preterite tense.

The subject of the first verb is *el profesor* (the professor) and of the other verb is *estudiantes* (the students).
In the sentence, we have two verbs which actions happened only once. Therefore, for both verbs, we will use the preterite tense. For the first blank we will use the third-person singular preterite form of the verb *estar* (be), which is “estuvo”.
For the second blank, we will use the third-person plural preterite form of the verb *aprender* (learn), which is “aprendieron”.

estuvo; aprendieron