Answer:
Using the past perfect tense, the sentence becomes:
Virtual libraries had presented a new paradigm for learning in school libraries.
Explanation:
The past perfect tense is used to talk about actions that took place in the past before another action that also took place in the past. Let's make a simple timeline to represent that:
o_____________o_____________o______________o_____________o
past simple present simple simple
perfect past perfect present future
For example, suppose you washed the dishes. Your mother arrived after you washed the dishes. Thus, you can use the past perfect to express the first action. The structure is subject + had + main verb (past participle):
I had washed the dishes before my mother arrived.
Having that in mind, we can change the sentence in the question using the past perfect to become:
Virtual libraries had presented a new paradigm for learning in school libraries.
