Hi, based on the example you pointed out in the comments, I don't think that you are expected to describe the situation, so much as 'narrate' the story. e.g. http://www.eiken.or.jp/eiken/en/downloads/files/Sample-2ji-2kyu.pdf shows a cartoon that has three frames / pictures. In other words, they want you to describe the story in the cartoon in words, rather than in pictures. They want you to show that you understood the story, by repeating it in English. So - rather than think about describing the picture, I think you should try to describe the story that the cartoon is telling. Does that make sense? Here is my version of that story: One day, Mr Sato was asked something in English by a customer at his bookstore. He had to apologise to the customer, and tell her that he did not understand English. Luckily, one of his staff could speak English, and came over and helped the customer. Mr Sato realised that if he learnt English, he might be able to help the customers himself. Perhaps it might even be fun to learn a new language. So, he enrolled in a class, and the next week, he started to learn English himself. As you can see, it is different to the model answer in the test, but I think it describes the same situation. I don't think you are expected to describe the picture. I don't think you should mention things like the fact that he has a green overall, or that the teacher is blonde. Just tell the story.

Grade-2 test Sample topic card. There are three cartoon(not picture?) in it. I have to describe the situation or make a story that match the cartoon.

Is it one of the tests at http://www.eiken.or.jp/eiken/en/downloads/ ? I can't see any that ask you to describe the picture. They seem to either you specific questions about the picture, or there are cartoons that describe a situation, which you need to put into words. Is that what you mean?

絵についての質問ですか。たとえば、この写真についてを書いてください。

Thank you for your comments and I'm sorry that I didn't explain it. The test is Eiken which is famous in Japan. I wrote "describe the situation" but I should write it like "make a story of three picture". Do you have any good expressions in that question?