Consider the following premises. For all y_1, if y_1 works, then y_1 is drinking water. For all y_1, y_1 will not work. There is at least one y_1 for which if y_1 drinks water, then y_1 is working. Can we infer the following from them? For all y_1, y_1 will drink water.
 From the fact that for all y_1, if y_1 works, then y_1 is drinking water, and that there is at least one y_1 for which if y_1 drinks water, then y_1 is working we can infer that there is at least one y_1 for which y_1 will work if and only if y_1 will drink water. Finally, from the fact that there is at least one y_1 for which y_1 will work if and only if y_1 will drink water, and that for all y_1, y_1 will not work we can infer that there is at least one y_1 for which y_1 will not drink water, which contradicts that For all y_1, y_1 will drink water. Therefore, the answer is no.