There are four answer here.I really don't know ( ) .

同学,很高兴回答你的问题
正确答案：选【 A 】
即：There are four answer here.I really don't know which to choose.
翻译：有四个答案,我真不知道要选择哪一个.
解析：which to choose 既是to choose作which的后置定语,而且which又是to choose的宾语,当动词不定式作定语时,必须要放在被修饰的词的后面,所以A是正确答案.
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