Experiments of this kind __________ in both the U. S. and Europe well before the Second World War.
At the foot of the mountain, .
The traffic rule says young children under the age of four and less than 40 pounds must be in a child safety seat.
Today's children are raised in a way that is totally different from how their parents were___.
Wilma became the first American woman to win three Olympic gold medals in track, _____ made her mother very happy.
She went to the bookstore and bought