The flu is believed ________ by viruses that like to reproduce in the cell inside the human nose and throat.
Deaf people talk ________.
A dark cloud is a _______of rain.
Since advertising can increase sales of production, _____it can _____the price.
– What are you advertising ______? ---________. I need a place to stay at.
– Do you have any idea which to choose? --- Well, you’d better take this one. It’s ______in price and good in quality.