Consider the following premises. For all x_8, if x_8 were a doctor, then x_8 is drinking water. For all x_8, x_8 will drink water if and only if x_8 will write a letter. For all x_8, x_8 is a doctor if and only if x_8 is an office clerk. For all x_8, x_8 will not write a letter. Can we infer the following from them? There is at least one x_8 for which x_8 is an office clerk.
 From the fact that for all x_8, x_8 will drink water if and only if x_8 will write a letter, and that for all x_8, x_8 will not write a letter we can infer that for all x_8, x_8 will not drink water. From the fact that for all x_8, if x_8 were a doctor, then x_8 is drinking water, and that for all x_8, x_8 will not drink water we can infer that for all x_8, x_8 is not a doctor. Finally, from the fact that for all x_8, x_8 is a doctor if and only if x_8 is an office clerk, and that for all x_8, x_8 is not a doctor we can infer that for all x_8, x_8 is not an office clerk, which contradicts that There is at least one x_8 for which x_8 is an office clerk. Therefore, the answer is no.