A. 〈元素名〉文件或超文本〈/元素名〉 B. 〈元素名属性名="属性值"〉文本或超文本〈/元素名〉 C. 〈/元素名属性名="属性值"〉 D. 〈元素名〉
A. twice the crankshaft speed B. half the crankshaft speed C. the same speed as that of the crankshaft D. a speed independent of that of the crankshaft