What are the keywords in the following sentence? what type of rock is this where or how is it formed
form, rock, type

What are the keywords in the following sentence? a city in the centre is packed with shoppers and visitors to the market
centre, pack, shopper

What are the keywords in the following sentence? the rising sun obscured behind a cloud as seen from the shore on the island .
cloud, shore, sun

What are the keywords in the following sentence? nurses looking at a medical chart in hospital
hospital, look, nurse