The next two passages have the topic sentence underlined. With that controlling idea in mind, find the one sentence that has been inserted that does not belong there because it breaks the unity. Cross out or highlight the sentence. I walk out along the fence line, gather up my lanterns, and station them around the plane. From the looks of the weather, it’s not likely that I can take off before sunrise. If I drain the engine and tie my DH to the fence, I can ride to town on the mail truck and get a night’s sleep. But then it would take two men, at least, to start up tomorrow morning, even if I pour boiling water into the radiator. Once a Liberty cools off, it’s a devil’s job to get it running again. The ground is starting to freeze; a sharp ridge dents the sole of my sheepskin moccasin. And you can’t ask help from just anybody who comes along; it takes training to handle either throttle or propeller. I’d probably have to phone for a mechanic from Lambert Field. No, I’ll stay with the plane, and start the engine every twenty minutes. That will keep it warm.