Sorry for the strange description in the title, but I've been out of school too long to remember what this is called. However, in a recent proofread of some writing I did, I realized I do it a lot, and I can't decide whether it's better to leave it in or not. I really don't even know what it's called, but I see lots of professional authors use it. Here's some examples. Jimmy yanked hard on the pole, loosening it from the rock. Jimmy yanked hard on the pole and loosened it from the rock. A bird exploded out from the shaft, zooming across the room and knocking over a pile of books. A bird exploded out from the shaft, then zoomed across the room and knocked over a pile of books. Which is "better?" And why? What's the logic behind stuff like this? I can't decide for the life of me and it's driving me nuts.