He pretended _______ when his mother stepped into his room.
_________ the problem of land erosion getting more serious, the government is searching for a way to deal with it.
-Mom’s gift? She _______ have chosen a better one for me.-She must be very happy to know it.
Everybody said it was an ideal marriage; no one had ever known ______ couple.
Soccer is the most truly international team sport, but there’s still some question _______ whether it should be called a game or open warfare.
In order to __________ a good command of German, she quitted her job and went to study in Germany.