把复合句改成简单句，谢谢

简单句变复合句:

1. As the United States is a country of immigrants, it enjoys a wide variety of ethnic food.
2. Because Americans have vast ethnic choice, they can enjoy food from all over the world.
上述两个用原因状语从句进行改写。

3. When you are ordering Italian food, you choose one main dish to eat yourself.
此题其实就是时间状语从句的省略形式。

确定是复合句改成简单句吗？是简单句改成复合句吧。1.The United States is a country of immigrants,so it enjoys a wide variety of ethnic food.2.Americans can enjoy food from all over the world.3.When you order Italian food,you choose one main dish to eat yourself.前两句是把分词作原因壮语该为原因壮语从句；最后一句是把连词加现在分词作时间壮语该为时间壮语从句。