All I have to do is learn English,看了有些答案说是All I have to do is to leatn English,只是省略

all 是主句的主语；is 是主句的谓语；learn English 是省 to 不定式,在定语中作表语.
I 是定语从句的主语；have to do 是定语从句的谓语；关系代词 that 作定从的宾语,但被省略了.
主句：All is to learn English.
从句：（that ) I have to do
动词不定式在作表语时,可以省略不定式符号 to.all 作先词指物时,关系词只能用 that ；关系代词在定语从句中宾语时,可以省略.
句意：我必须做的事情就是学英语.