What is the rule in the conjunction of sentences that are using present perfect?

Question

I'm using conjunction between two phrases, both of them are using the present perfect tense.

My question is:

• should I repeat the auxiliary verb have/has or I should use it only the first time? and what is the grammatical rule here?

"Something has done the first thing, and made the second thing"

or

"Something has done the first thing, and has made the second thing"

Thanks in advance

Answer 1

No need to repeat it if you have a parallel structure.

• He has cleaned the room and swept the porch.
• He has done his homework and picked up the clothes in his room.
• She has eaten the haddock but not touched the potatoes.

There is no need to repeat the auxiliary in a parallel structure.

Non-parallel structure:

• He has cleaned his room but did not wash his clothes.