Mr. Zhang once taught in a remote village in Anhui province as a volunteer, which was ______ only on foot.
There is no ______ swimming-pool in this school and the students often go to swim ______.
You have no idea what I’ve had to ______ during the last few months.
Mary had to call a taxi because the box was_______ to carry all the way home.
As he was about to go out to search for Mary, she happened ____.
I wonder how he _______ that to the teacher.