33. Once ____you may feel uncomfortable.
The chairman thought _____ necessary to invite Professor Smith to speak at the meeting.
Eating too much fat can______ heart disease and cause high blood pressure.
Her __________ feeling about him made him ____________.
Some people get in touch with each other by mobile phones__________ others keep contact with each other by e-mail. A. while B. before C .when C. since
________ surprised the hostess most is _________ one of her friends left the party without saying a word.