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1)Make sure you wear a hat when you're out in the ____ weather.
2)we __ for three hours before we decided to take a break.
A. must be trekking
B. had been trekking
C. have been trekking
3)A good way to __ a problem is to think about it calmly and carefully.
4)Sue wanted to change the appearance of her living room, so she _____ by a professional interior designer
A. decorated it
B. had it decorated
C. had decorated it
5)Neither Annabel __ Sue has ever flown in a plane