根据短文内容，选择最佳答案，并在答题卡上按要求作答。
B
Scientists say life will be very different in 2050.
First, there will be no TV channels (频道) in 2050. People will choose a program (节目) from a computer and watch it on TV. In 2050, we will get information from the computers only.
Second, water will be a big problem in 2050. In many places, people won't have water to drink.
Third, cars will use new and clean fuels (燃料) and they will go very fast. There will be a computer in every car. And the computers will control the cars and there won't be any accidents (事故).
=1时，去分母正确的是（ ）．