He had nearly lost his balance as he Apparated onto the top step just outside the front door, and thought that the Death Eaters might have caught a glimpse of his momentarily exposed elbow.
他刚才幻影显形到前门外台阶顶上时差点失去平稳，心想食死徒可能看到了他一时暴露在外的胳膊肘。
2
Walk forward. That means tilt slightly forward from the waist when walking. Bend your arms at the elbow and pump them as you walk. This helps to create momentum and balance.