What are the keywords in the following sentence? Pair of cross country skiers on well traveled snow field near buildings.
building, field, pair

What are the keywords in the following sentence? politician visits baroque structure at the end of his meeting with religious leader
end, leader, visit

What are the keywords in the following sentence? an envelope containing a letter that ultimately found its way to its recipient .
contain, envelope, letter

What are the keywords in the following sentence? The front of train makes its way along the tracks.
front, track, way