悬垂修饰语(Dangling Modifiers)
　　所谓悬垂修饰语是指句首的短语与后面句子的逻辑关系混乱不清。例如：At the age of ten, my grandfather died. 这句中at the age of ten只点出十岁时，但没有说明“ 谁”十岁时。按一般推理不可能是my grandfather， 如果我们把这个悬垂修饰语改明确一点，全句就不那么费解了。
　　改为：When I was ten, my grandfather died.
　　例1. To do well in college, good grades are essential.
　　剖析：句中不定式短语 to do well in college的逻辑主语不清楚。
　　改为：To do well in college, a student needs good grades.