There is reason to believe that most writers have difficulty in ______ the opening paragraphs of their papers.
Bill was doing a lot of physical exercise to build up his______.
—I wonder ______ you’ll water this kind of flower. —Every other day.
. She brought with her three friends, none of ______ I had ever met before.
. — Why does the Lake smell terrible? —Because large quantities of water______.
Peter’s jacket looked just the same as Jack’s, but it cost ______ his.