# using two passive verbs with a same subject

I have problem with the statements like the following:
-These two parameters are selected and changed ...
-These two parameters are selected and are changed ...
which one is correct?

• If no confusion arises (It was subjected to severe testing and changed), drop the second auxiliary. – Edwin Ashworth Mar 10 '18 at 18:00
• Two sentences are different, but just being different doesn't automatically make one right and the other wrong - grammatically or otherwise. The case must be made for each sentence on its own merits. – Lawrence Mar 10 '18 at 18:02
• Grammatically, there is no issue with either. – The_Arcadian Mar 10 '18 at 19:35

In the simple example that you give, both are grammatical, but omitting the second are is far more idiomatic.

The greater the separation of the second passive verb from the auxiliary, the more likely that the auxiliary will be repeated.

The parameters are selected by the Product Revision Committee after consultation with Marketing, Costing, and Engineering and are changed by Programming.

• That's a beautiful example, and I had to answer to explain how it was beautiful. A comment just wouldn't do it justice. – Edwin Buck Oct 10 '19 at 6:17

When using a conjunction like and, an old rule is that the conjunction should join two identical grammatical structures.

Your sentence has two kinds of verb clauses "are selected" and "changed". I don't think people would be confused by combining them, but it is better to mimic clauses across the conjunction that binds the clauses.

Jeff's example is wonderful, as it demonstrates two conjunctions, with two different kinds of clauses. The first "and" joins

noun, noun, and noun

While the second "and" joins two identical complex structures

are 'verb' 'prepositional phrase' and "are 'verb' 'prepositional phrase'

How identical the phrase are is a matter of debate, but the closer the grammar matches, the easier it is to read the sentence without extra work.

• We used to call it parallelism and designated it as a rule of rhetoric rather than grammar. – Jeff Morrow Oct 10 '19 at 13:53
• @JeffMorrow Thank you. I'll try to remember the term. I find it interesting it was considered a rule of rhetoric. It seems so grammatical! :) – Edwin Buck Oct 11 '19 at 1:01