Answer: He is reading in the library. According to the above, he is not at home, but reading in the library, explaining what he is doing at the moment. In the present continuous tense, it is composed of am/is/are+doing, the subject is he chooses is, and the present participle of the verb read is used to read books. Make an adverbial of place in the library. So the answer is that he is reading in the library. ..