I had alittle trouble learning English grammar(learning为什么加ing)

问题描述:

I had alittle trouble learning English grammar(learning为什么加ing)

这里省略了 IN
在哪里有麻烦: have trouble (in) doing sth

中文意思:我在学习英语语法方面有些困难.
全文应该是:I had a little trouble in learning English grammar.
有时侯为了省事人们会省略"IN"