What's another name for the United States

What if puerto rico required all cement to carry a label with the location where it was manufactured and the date it was packaged? does that regulation discriminate against interstate manufacturers?

Iopened the door quietly, then stood in the doorway rewrite using ..ing participle

3. what is the purpose of a lead sentence or paragraph? to display your most convincing reasons and arguments to you revise the overall structure of your work to interest readers and introduce your writing style to add details and elaborate on your ideas