expand it on the base of their work

[floratang]

He said that they had worked on the project for 10 years and Tom could expand it on the base of their work.
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I don't undertand "expand it on the base of their work".

[Tdol]

Use what they had done so far to widen the scope of the project.

[floratang]

There are 3 explanations of the verb "expand" :

1.to become larger in size, number, or amount, or to make something become larger
2.if a company, business etc expands, or if someone expands it, they open new shops, factories etc
3.to become more confident and start to talk more

Which one should I choose to the sentence?

[Tdol]

There's not a lot of difference between the first two definitions, and it could fall into either, but I'd choose the first.