Obviously, the book is for children aged between three and six.

I recommend an English-Chinese dictionary, which I thought would be of great help to his studies.[ ]

Why are you late, Jim—Because there _________ a lot oftraffic when I came here.

The plan __________just because people were unwilling to cooperate

．—-Whyis the university doing so much building—-______number of students______sorapidly.