Because I have thought that I have to send long sentence. The other day I found that it was mistake. I was very shock. It was very hard for me to think of long sentence. According to the degree of difficulty, we write the answer longer than first essay.
First essay is abstract.
When the title is difficult, I worry about what to write. But when the title is easy, I can write first essay longer. The other hand, questions from partners are clear to write about things. And partners send many questions to me. I have to answer that questions.