通读全文，根据短文内容的理解，选择最佳答案填空。
My holiday is coming.Yesterday I asked my American friends about the best way to travel around the United States. They said it was best to travel by 1 and gave me the 2.
To fly, of course, is the fastest way, but one can't see anything during a 3 except the blue sky and white clouds. So it is not very interesting for one who wants to see the 4.Besides, the plane ticket is very 5.
To travel by train is 6, because passengers can walk and buy food and drinks on a train. They can also see cities and the country through the windows. But trains don't leave or 7 at a place every day, and don't go to many cities.
To travel by bus is easy, cheap and convenient, though not so fast as travelling by plane or so 8 as by train. You can find buses almost in every city. That makes travel arrangement easy.
I take their 9.Now I have decided to go on an interesting 10 by bus to the east coast.
