Consider the following premises. There is at least one x_4 for which x_4 will drink water if and only if x_4 will read a book. For all x_4, x_4 will read a book if and only if x_4 will drink water. For all x_4, if x_4 reads a book, then x_4 is drinking water. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_4 for which x_4 will drink water if and only if x_4 will read a book.
That is one of the premises. Therefore, the answer is yes.