Write the verb in parentheses in the imperfect tense.
. (ser)
write the verb in parentheses in the imperfect tense.
la selva. (ir)
write the verb in parentheses in the imperfect tense.
ellas la jungla. (ir)
write the verb in parentheses in the imperfect tense.
tú . (saber)
write the verb in parentheses in the imperfect tense.
el hojas verdes. (comer)
write the verb in parentheses in the imperfect tense.
yo nada. (ver)
how would you say "i used to look at" using the verb mirar? just write the the subject.
how would you say "i used to sing" using the verb cantar? just write the the subject.
write the verb in parentheses in the imperfect tense.
la clase de historia. (estar)
write the verb in parentheses in the imperfect tense.
en costa rica. (estar)

Era is the conjugation of the verb ser that matches the first person singular (yo) in the imperfect tense. In general, the imperfect is used to talk about past actions, conditions, or events that occurred regularly or frequently or that were in progress in a moment in the past. The verb ser is being used here as occupation, Basically, it's what someone does for a living or as a hobby. Since the word profesora is a feminine noun, this teacher is a woman. Therefore, I was a teacher. Finally:

Yo era profesora.

Íbamos is the conjugation of the irregular verb ir that matches the first person plural (nosotros) in the imperfect. For irregular verbs, you must learn by heart conjugations for each tense because there is no any rule that irregular verbs must follow. So, we used to go to the jungle. Finally:

Nosotros íbamos a la selva

Iban is the conjugation of the irregular verb ir that matches the third person singular in the imperfect. In this sentence, only women used to go to the jungle. We can know this because of the subject pronoun ellas that is feminine and plural. Finally, we can write this sentence as follows:

Ellas iban a la jungla

Sabías is the conjugation of the regular verb saber that matches the second person singular in the imperfect. This verb is an er verb because it ends in er. To conjugate it for the second person singular, remove the er ending and add ías to the end of the word. On the other hand, you didn't know anything. It is easy to see that this is a negative sentence. Negation is an expression that means no and is used to contradict some or all of the meaning of a positive sentence. Finally:

Tú no sabías nada

Comía is the conjugation of the irregular verb comer that matches the third person singular in the imperfect. This verb is an er verb because it ends in er. To conjugate it for the third person singular, remove the er ending and add ía to the end of the word. On the other hand, The bear used to eat the green leaves. Finally:

El oso comía las hojas verdes.

As we said above, the verb ver is one of the three irregular verbs in the imperfect. So you must learn by heart that the conjugation of this verb that matches the fist person singular in the imperfect is veía. On the other hand, this is a negative sentence. Finally:

Yo no veía nada.

In this exercise, we must use the verb mirar. Thus, we'll conjugate it in the imperfect matching the first person singular, which is yo. Accordingly, this conjugation is miraba. Keep in mind that in Spanish it is common not to include the subject pronoun in sentences. Finally, by writing miraba, every one will know that I am the one who used to look at.

Since we must use the verb cantar, we'll conjugate it in the imperfect matching the first person singular. Therefore, this conjugation is cantaba. The conjugation follows the following rule: The verb cantar is an ar verb because it ends in ar. Therefore, for the first person singular take away the ar ending and add aba to the end of the word.

Estaba is the conjugation of the verb estar that matches the first person singular (yo) in the imperfect tense. The verb estar is being used here as location, describing where a person was temporarily. So I was in history class. Therefore, we can write this Spanish sentence as follows:

Yo estaba en la clase de historia.

Estábamos is the conjugation of the verb estar that matches the first person plural (nosotros) in the imperfect tense. The verb estar is being used here as location as well, indicating that we were in Costa Rica, which is a country in Central America, Therefore, we can write this Spanish sentence as follows:

Nosotros estábamos en Costa Rica