13. For many cities in the world, there is no room to spread out further, _______ New York is an example.14.
Neither Jack and Tom ___ Mary ___ at home that day.
The River Nile ___ flood large areas, but now the water of it ___ produce electricity.
We learned a lot from her father, an engineer ___ does research ___ science.
You should make a careful plan ___ the experiment.
Here’s my card, let’s keep in ___.