He kept thinking of the question whether it was ____ for his father to change the habit of a life time in such a short time.
Science fiction writers often write about _______will happen in “tomorrow’s world”.
Medicine and food ________ to the flood areas soon.
When _______ comes to advertisements, we must all use our intelligence.
________ he found the idea interesting, it was too difficult to be of practical use.
As they were walking around, they noticed a man _______ against a tree.