—I’m afraid you missed a fantastic lecture yesterday. How come you were absent from it?—If you _______ know, I asked for a day off and visited a relative of mine in hospital.
---- Putting on a happy face not only helps us make friends but also makes us feel better. ---- _______.
The Human Development Report shows that we are making progress in many different aspects but ______we need to make great efforts.
Coal was formed out of dead forests through a long _____ of chemical changes.
The reason _____ the president of Czech is widely discussed recently is _______ he was seen “to steal” a pen at a press conference in Chile.
The expert warns the Internet users not to ______ their personal information to strangers.