Nature reserves are very important for preserving many animals and plants, which would _______ run the risk of becoming extinct

To live on Mars, you need to wear boots which ________ to prevent you from floating off into space.

ses, ____were already full, were surrounded byan angry crowd

Unluckily, a ship from South Korea sank into the sea ________ 2014.

o his joy, the old man may be able to get ahardship _____ from the government, which covers his expense