What revision should be made to maintain parallel structure? sentence 1 should be revised to read, "outside the snow fell; inside the heater came on with a distant roar." sentence 2 should be revised to read, "outside, the wind howled through the big oak; inside, a log snapped in the fireplace." sentence 3 should be revised to read, "outside, footsteps walked hurriedly past the window; inside, the cat stretched and purred." sentence 4 should be revised to read, "in the night, an owl hooted; in the room, a page turned."