------------a new pair of sports shoes,Ann?

答案：D.
翻译：--安,你需要一双新的运动鞋吗?--我的（运动鞋）还可以（穿）.你不必为我买双新的.
此题考查need作为情态动词/行为动词的用法区别.
1.need如果做情态动词,其后直接加动词原形.变成一般疑问句时,直接把need提前至句首.
AB中的确把need提前至句首,说明视其为情态动词,但是句中却没有其他任何动词原形,错误.
need如果视为情态动词,则问句可以说：Need you buy a new pair of sports shoes,Ann?
need如果视为行为动词,则问句为：Do you need (to buy) a new pair of sports shoes,Ann?
2.同样,need作为情态动词时,其否定句必须直接在need后面加上not,其后还是动词原形.
C中使用needn't,说明视其为情态动词,但是其后不是动词原形buy,而是不定式to buy,错误.
need如果视为情态动词,则答句为：You needn't buy a new pair for me.
need如果视为行为动词,则答句为：You don't need to buy a new pair for me.
3.另：如果need为行为动词,则其疑问句/否定句必须借助于助动词do/don't,does/doesn't,did/didn't等进行变化,本身有时态/数的变化（needs/needed）.且其后不能直接动词原形,而是使用一下结构：need sb/sth,need to do sth,need sb to do sth,need doing等.