How did the crusades accelerate change in europe?

Suppose you need to verify how correctly use commas you open ur english textbook and scan the chaper titles in which one would most likey find the information you need

How do i can change this sentence : a modern physician in a small town not only is proficient in general medicine but surgery as well. to parallel structure?

Buck did not cry out. he did not check himself, but drove in upon spitz, shoulder to shoulder, so hard that he missed the throat. they rolled over and over in the powdery snow. spitz gained his feet almost as though he had not been overthrown, slashing buck down the shoulder and leaping clear. twice his teeth clipped together, like the steel jaws of a trap, as he backed away for better footing, with lean and lifting lips that writhed and snarled. read this passage. explain what the conflict shows about buck and spitz.