Answer:
1. ha estado
2. habían reservado
3. he hecho
4. había llegado
Explanation:
The perfect past tense is a tense used to:
* Talk about actions that have happened a short time ago: Esta mañana he visto a María.
* Talk about actions that we don't want to say when they happened: Antonio ha estado enfermo varias veces.
* With the adverbs still and still: ¿Todavía no has terminado los deberes?
It is formed with the present simple of the verb to have as auxiliary and the participle of the main verb.
