The tiger, once a ____ animal to humans, is now ____ of disappearing on the earth.
He went from door to door, _______ waste papers and magazines.
. _______ the office, the foreign visitors were shown round the teaching building.
With winter _______ on, it's time to buy warm clothes.
Deeply _______, I thanked her again and again.
_______ the house on fire, he dialed 119.