What do you think you __________ at this time next year?
His purpose ________ going to the US is ________ for his uncle.
The scientist________ the behavior of the mice after they were given the drug.
It may rain,but I shall go out ________.
Though plastic bags really bring convenience to us,they also ________ many problems for the environment.
He was observed ________ into the house before the owner came back.