The number of people invited to the party ______ fifty, but a number of them ______ absent for different reasons.
.The United States signed up Friday for the 2010 Shanghai World Expo,_______it the last major country to join the event.
.In this experiment, they are wakened several times during the night and asked to report what they__________.
--I hear Michael is in hospital. ----Oh, really? I____know. I______go and visit him.
Children find_____difficult to sit for hours with little to do while flying.
---Must I see a doctor right now? ----No, you______see a doctor for the time being.