General question about when to use "is" and "does" as I keep interchanging both of them.
In the sentence
"What time does the pharmacy open?"
Why can't I write this:
"What time IS the pharmacy open?"
I know that
"when is the pharmacy open?"
is correct so does
"When does the pharmacy open?"
work as well?
I am having trouble learning the difference of when to use "is" instead of does. Are there any instances of when they are interchangeable such as "When is the pharmacy open" and "When does the pharmacy open?" mean the same thing? Should I always assume that they are never interchangeable?