What are the keywords in the following sentence? stacked shipping containers in a port
container, port, stack

What are the keywords in the following sentence? mass transportation system carried passengers virtually the same number as the year before .
carry, passenger, system

What are the keywords in the following sentence? bright yellow wildflowers growing in the natural grass at reserve
grass, grow, wildflower

What are the keywords in the following sentence? sunrise crepuscular rays radiate through clouds and the sky above a pasture
cloud, pasture, sky