All I have to do is learn English.这句话语法对吗?

All I have to do is learn English.这句话语法对吗? All I have to do is learn English.中的learn用法对吗 All I have to do is learn English.这句里learn是动词,前面干吗用is all i have to do is learn english.为什么不是all i have to do is l All I have to do is learn English. 中的learn是不定式吗? All I have to do is learn English,看了有些答案说是All I have to do i All I have to do is learn English 是对的吗 all i have to do is learn english是否错了? 请问这个句子中all I have to do is learn english.is跟learn不是都是动词吗?为什么 All I have to do is learn English."all"可以换成"what"吗?换过有区别吗? What I have to do is learn English What I have to do is learn English.