这个国家的东部地区多山。

The ___eastern part of the country is very mountainous.

之后你可以乘火车前往瑞士的东部地区。

After that you can catch a train which takes you to the ___eastern part of Switzerland.

许多人喜欢东部菜系，因为它有独特的味道。

Many people enjoy the ___eastern cuisine for its unique flavors.