She was the firstabout it.A. to learnB. learningC. learningD. to have learned

问题补充：

She was the firstabout it.

A. to learn

B. learning

C. learning

D. to have learned

答案：

(答案→)A. to learn

B. learning

C. learning

D. to have learned

解析：作序数词或带有序数词、形容词最高级的名词的定语时用动词不定词，不用现在分词。