I don't know either the following constructions are a phrase or a clause?
1) wash the dishes
2) do the laundry
3) take out the garbage
In my opinion, they are all phrases or verb phrases to be exact.
Am I right?
These are all examples of commands, in which the subject (you/you all) is omitted. Although the subjects are not explicitly written, they are implied, so these examples are in fact complete sentences.
See this post for more information: https://english.stackexchange.com/questions/124250/are-commands-complete-sentences
They could be either.
In the sentence
Wash the dishes!
The phrase is a complete clause, and a complete sentence. It is an imperative.
In the sentence
We wash the dishes on Monday.
The phrase "wash the dishes" is not a complete clause in this example, it is the verb phrase in a longer sentence. This sentence only has a single clause.
So the question cannot be answered. A word or phrase only has a grammatical function when placed in a sentence.