英语一二十年怎么说

"A decade" refers to a period of ten years. So "a decade" in Engpsh can be used to refer to a period of ten years. For example, "the past decade" could refer to the ten years that have just passed.

If you want to refer to a specific number of decades, you can use the word "decades" followed by a number. For example, "two decades" would refer to a period of twenty years, and "twenty decades" would refer to a period of two hundred years.

Here are a few examples of how you could use these phrases:

"The past decade has seen a lot of changes in technology." (refers to the ten years that have just passed)
"It's been over two decades since I graduated from college." (refers to a period of more than twenty years)
"Twenty decades is a long time to wait for something." (refers to a period of two hundred years)