not matter whose fault it is, my son made mistakes in grammer, meaning that he has some problems with grammer. He never never complained about us. My wife and I, as parents, sometimes wonder why he kept on making grammer mistakes, while were doing well on all other sections. We speculate that when we talked to him, we many times used the wrong grammer. Maybe this negatively affected his feeling on grammer. Like I said, it is his duty/job to learn good grammer (or anything). We as parents just think back to see the reason why he is particularly not good at this area in his act and sat. Not trying to find any excuse for him. Actually we always tell him do not try to find any excuse for one's own mistakes; few people want to hear ur excuse.