单选题
The little boy had no choice but to look on ______ as his mother was seriously injured in the traffic accident.
【正确答案】
D
【答案解析】本题考查词形的转换。考查的词根help是名词或动词，意为“帮助”；加后缀-less变否定形容词，意为“无助的”；再加-ly后缀变副词，意为“无助地”；没有加-ness变名词的形式。该句意为：当他的母亲在车祸中受伤时，那个小男孩没有别的选择，只能无助的旁观。