Answer:
When we (were) young, we (weren't) very outgoing.
(Call) me in, five minutes?
(Catch) all of the bank robbers this morning?
The Earth (can not be) flat.
Answer:
The search term that would be most helpful in finding this information is World War II AND rescue efforts AND Jewish refugee children
Explanation:
In order to get the best results from an internet search we need to use keywords that are more specific towards the information we want to collect, then the third option is the one that has the most complete combination of topics and does not add anything that could lead to the appearance of useless sources of information.