Answer:
Yo entraba datos en la computadora cuando tú me llamaste.
Step-by-step explanation:
In English this means: I was entering data in the computer when you called me. The tenses used are the imperfect in the first verb "entraba" and the preterite in the second verb, "llamaste". This structure is used to talk about certain action in the past that is taking place and gets interrupted by some other action. In this case, the data entering gets interrupted by the phone call.