31. --______ one and a half days enough for the painting to be finished? --I don’t think it’s enough and only after _________ go on with it.
Her question was so difficult that I could not __________ of it at all.
After staying in hospital for long, the patient was advised to go to the seaside to __________ his health.
I was walking down the street, when I suddenly saw a car __________ a huge pine.
I soon found that the work I was doing had already been done by someone else —__________ I was wasting time.
__________ with foreign countries can bring us much information about the world.