是I find learning English difficult.还是I find learning English is difficult.为什么？

都对.
I find learning English difficult
这个固定搭配find sht adj. difficult这里是宾语补语. .
I find learning English is difficult.
这里是宾语从句. learning English is difficult是宾语. 中间有省略that.
一般用第一种形式

I find learning English difficult.

或者

I find that learning English is difficult

都行

I find sth. adj.

或者

I find that sth. is adj.

不对的

虽然learning 做动名词 不能用learning English做宾语了

要变成I find english-learning difficult

后面的句子可以的 动名词做主语

实际上是I find that learning English is difficult
省略了that

两个都对
第一个是宾语补足语find +sth.+ adj.

第二的是从句find +that 从句

后一句对,省略that的宾语从句,但不能省略从句中的系动词is

I find learning English difficult