i couldn't study grammar very good 哪儿错了?

i couldn't study grammar very good 哪儿错了? To study grammar is very b------ I sometimes study grammar.有语法错误吗? Luckily , I study very good是病句么 How do you study English ?I study English_____  grammar I couldn`t help i couldn‘t是什么意思 I couldn't help i couldn't agree how to study very good? Is you father in the study哪儿错了 it is china dish .i like it very much.哪儿错了