I often meet this kind of sentence "If it is to operate....."
Can you explain me the role of "is to"?
I guess it is for emphasis, but Im not sure
You can insert a mental "going". "If it is going to operate, you'll need to insert a battery." You can also say:
"To make it operate, ..."
"To get it to operate, ..."
"For it to operate, ..." "In order for it to operate, ..." ...
I don't think it's for emphasis. If it is, what is the base form?