Here are some examples:
* The U.S. government
* Traveling to the U.S.
* The U.S. economy
However, it's important to note that:
* You should not use the abbreviation "US." This abbreviation is considered informal and is not typically used in formal writing.
* Use the abbreviation sparingly. It's generally considered best to spell out "United States" the first time you use it in a piece of writing, and then use the abbreviation afterward.
* Context is key. The abbreviation "U.S." should only be used when it is clear that the word "United States" is being used as a noun. For example, you wouldn't use "U.S." in a sentence like "They drove from Texas to the U.S." (as it's not a noun).
Overall, using "U.S." as an abbreviation is a perfectly acceptable practice, but it's important to do so correctly and appropriately.