The man in the middle is the heaviest.
The man in the middle is heavier than the other two.
The woman on the left is smarter than the man on the right.
The man isn't as smart as the woman is.
The woman is standing under a bridge.
The bridge is above the woman.
There is a bridge over the river.
The river is flowing beneath the bridge.
The water is flowing over a waterfall.
The waterfall is very high and beautiful.
People need passports to travel internationally.
Without a passport, you can not leave your country or enter another country.
You need a driver's license to drive a car.
It is against the law to drive without a driver's license.
Many people use credit cards to buy things on credit.
When you have a credit card，you don't need to carry cash.
Smartphones are very useful and can do many things.
You can use them to make phone calls, play games or go shopping on the internet.
We need to buy tickets in order to take a train or watch a sports event.
You can often buy tickets online, and sometimes you can get a discount.
