Thank you so much for your comment!
My essay has more spelling errors than I expected
Such spelling errors may result from the fact that I was in a hurry and didn't check carefully after typing. I will try not to repeat this for the next essays.
As you say, my biggest problem lies in vocabulary. In fact, I am trying to improve it. I always find it hard to find the most suitable and formal words. Sometimes, I wonder whether a word used is right or wrong. But noone can help me.So, your correcting is really helpful.
But can't you score it so that I will know where i am?