The same verbs can be used under different contexts as either linking or auxiliary. why give example

How does nitrogen oxides are produced and their air environment impact

Describe the potential effects, on people, of unprotected exposure to the sun.give an example of 1 new thing have you learned about the sun’s uv rays.

Mr. thomas has an outstanding balance of $128.75 and owes a copay of $30.00 for today’s visit. how much money should be requested from mr. thomas at check out?