Answer:
1. se levantaron
2. desayunaba
3. llamó
4. dijo
5. era
6. salieron
7. había
8. conducía
9. leía
10. cruzaron
11. vieron
12. estaban
13. dieron
14. llegaron
15. había
Explanation:
1. It was eight when Catalina and Elena <em>woke up </em>to go to the center.
The time reference <em>eran las ocho</em> indicates this action happened in the morning so the verb we choose is <em>levantarse</em>. When it comes to the tense we should use, we consider again the time reference which indicates the precise time an action was executed. Hence we use the <em>preterito.</em>
2. Elena was having breakfast
3. when Daniel called to say he was ready.
In the sentence number one we used the verb <em>desayunar </em>meaning to have breakfast. The verbal tense we preferred here is the <em>imperfecto. </em>It is a descriptive tense and it is used to illustrate background action, the one that introduces central action, which is expressed with the verb 3.
Central actions are introduced with the <em>preterito</em>. It is used as a focus, as it gives importance to the action expressed by it. It usually has a precise time reference that indicates when the action was executed. Here it is the entire temporal clause <em>Elena desayunaba</em> that serves as a reference in time.
4. He told her again
5. that the date was at 10:30.
There is no time reference to justify the form of the verb <em>decir</em> but what we can see is that this sentence is the Spanish <em>reported speech</em>. Since we need to report somebody's words in the past, we use the introducing verb in the past tense. The verb <em>decir </em>has an irregular base for the <em>preterito:</em> DIJ-.
In the <em>reported </em>sentence we used the verb <em>ser </em>in the <em>imperfecto</em>. This so because of the sequence of tenses. In the direct speech, this part would be in the <em>presente</em>, and as for the reported speech, the Spanish rule of the sequence of tenses indicates that all <em>presente </em>becomes <em>imperfecto</em>. <em>Ser </em>conjugates in the <em>imperfecto </em>using the ER- base and the endings for the first (-AR) group present.
6. They went out at 9:30.
In this sentence we used the verb <em>salir</em> meaning to <em>go out </em>in the third person plural of the <em>preterito</em>. This form describes a simple, executed action that started and finished. It is an entirely executed action, and the use of the <em>preterito </em>is also justified by the time reference that specifies it: at 9:30.
7. It was still early and there was still time.
The Spanish verb <em>haber </em>is the equivalent of the English structure <em>there is/there are</em>. We used it here in the form of <em>imperfecto </em>as it illustrates circumstantial, background information. This is a descriptive sentence, it creates suspense until important actions are narrated.
8. Ellena was driving
9. while Catalina was giving instructions to reach the destination.
These two actions illustrated by the verbs <em>conducir </em>and <em>leer</em> happened simultaneously. We see that from the conjunction <em>mientras </em>which introduces the <em>imperfecto. </em>This type of action is used to define the background of the action, continuing in the same manner as the last sentence.
10. There was a lot of traffic when they crossed the bridge.
In this example we have one use of the <em>imperfecto</em>, había, to prepare the background for the main action: <em>cruzaron. </em>The <em>preterito </em>is here conditioned buy a time reference - the temporal clause. The main information is the crossing of the bridge, while the thick traffic is simply referential and could be left out.
11. They didn't see the office building
12. because they were lost.
This sentence gives the perfect example of circumstantial information used in service of the main information which is <em>action. </em>The main information illustrated by the verb <em>ver </em>is caused by the background information expressed by the verb <em>estar</em>. The important thing is that <em>they didn't see the building</em>, and the reason behind it is the fact that <em>they were lost.</em> Central vs. Background information.
13. They took many turns
14. until they finally came.
This sentence illustrates two consecutive actions that happened one after another. They bear the same type of information so the difference in importance is deleted. When we want to account on two or more executed actions having the same degree of importance, we use the <em>preterito</em>.
15. It was 11:15 already. But no one was there!
In this last sentence the verb <em>haber </em>gives information on what the girls caught on their arrival. It describes the condition of the room where the meeting was being held at. It <em>doesn't</em> account on any action, only background information and we get the feeling that some action is about to emerge. The text ends in <em>suspense</em>.