Q: Keywords: fill, train, travel, tree
What is a sentence that includes all these keywords?

A: A train traveling through a tree filled countryside.

Q: Keywords: root, tangle, tree
What is a sentence that includes all these keywords?

A: the tangled roots of a tree

Q: Keywords: activity, engage, kid
What is a sentence that includes all these keywords?

A:
An adult and a kid are engaged in an activity.