ask for help是一个完整的动词吗?应该ask sb for help 或ask for help from sb吧但总觉得ask for help 挺完整的..但既然有这种题目In the dark street ,there wasn't a single person___she could ask for help的话有ask sb for help 或ask for help from sb两种都可以 也至少说明ask for help 不完整 我说的对吗有ask sb for help 或ask for help from sb两种都可以的意思是用ask sb for help 横线上可以填that 或whom 用 ask for help from sb的话填from whom

In the dark street , there wasn't a single person___she could ask for help 这是一个定语从句。先行词在从句中做ask 的宾语。
ask 一般可以用于下列结构：

ask for sth 请求/要求（某物）
ask sb for sth 向某人要某物
ask sb to do sth 要求某人去做某事

额 后面说的我看不懂 总之我觉得 ask for help　是一个完整的动词
请求（寻求）帮助嘛，

ask for help 可以单独使用,如：He had to ask for help.他不得不请人帮忙.你说的句型也是对的.如：He had to ask the teacher for help.他不得不请老师帮忙.只有ask sb.for help,没有ask for help from sb....