There's nothing's as troublesome as a naughty clild.
没有东西比淘气的孩子更麻烦了。
I didn't think I'd see you here.
没想到会在这碰上你。
I was doing some exercises on the high-and-low bars. When I landed, I fell forward and hurt myself. Someone was standing too close and I knocked into him and fell over onto my shoulder.