问题详情

Certainly, the most popular method of traveling used by Americans is the privately-owned automobile. The vast majority of Americans have a car, and many families have two.【31】during your visit to the United States, you may decide to rent a car to travel outside the city or to travel to other parts of the country.
Car rental companies are【32】in the telephone book and are located in most cities and towns.【33】, there are usually rental cars at airports and train and bus stations. As is true everywhere in the world, you can rent a car【34】the day, week, or month. Some companies【35】have special weekend rates that you may find especially interesting if you have only a limited【36】of time to travel around the area you are visiting. Since each company has its own rules and rates, it is a good idea to【37】prices among companies to get the best rates to suit your purposes. For example, most car rental costs【38】how long you plan to keep the car and how far you travel. However, some companies may include gasoline in their rates, but【39】do not. Some companies require that you【40】the car to its starting point; others will permit you to leave the car in another city.
(31)
A．Some time
B．Sometimes
C．Sometime
D．Some times请帮忙给出正确答案和分析，谢谢！