What are the keywords in the following sentence? a city performs onstage during the concert at theater .
city, concert, perform, theater

What are the keywords in the following sentence? A climber scales the last cliff before the peak.
climber, peak, scale

What are the keywords in the following sentence? the sky is filled with a green aurora with tiny hints of red
aurora, fill, sky

What are the keywords in the following sentence? small bird with black mask singing while perched on a branch
bird, branch, perch, singing