What are the keywords in the following sentence? There are children building a frame for a structure.
build, frame, structure

What are the keywords in the following sentence? morning mist on the field near trees
field, mist, tree

What are the keywords in the following sentence? police clash with students during a protest on tuesday night .
clash, police, protest, student

What are the keywords in the following sentence? A train with steam coming out is on the tracks.
come, steam, track, train