The flu is believed ______ by viruses that like to reproduce in the cells inside the human nose and throat.
--- This must be a footprint of a tiger. --- It ____ be. A tiger’s should be much larger and deeper than this.
Some people are holding their umbrellas ____ it is raining.
That statue was set up ____ those who died in the battle.
Dr. Stockton was much ____ by his colleagues for his research in astronomy.
---Did you enjoy the party last night? --- _______! Everybody was in high spirits.