Although chatting on line has exploded in popularity in recent years, there is no ________ for a face-to-face conversation.
The number of people invited ______ fifty, but a number of them _____ absent for different reasons.
When and where to go for the on-salary holiday ______ yet.
Every possible means ______ to prevent the air pollution, but the sky is still not clear.
E-mail, as well as telephone,______ an important part in daily communication.
---“Each of the students, working hard at his or her lessons,_____ to go to university.” ----“So do I.”