Consider the following premises. There is at least one x_8 for which x_8 is sad if and only if x_8 is a carpenter. For all x_8, x_8 will not take a plane. For all x_8, if x_8 were a carpenter, then x_8 is taking a plane. Can we infer the following from them? For all x_8, x_8 is sad.
 From the fact that there is at least one x_8 for which x_8 is sad if and only if x_8 is a carpenter we can infer that there is at least one x_8 for which if x_8 were sad, then x_8 is a carpenter. From the fact that for all x_8, if x_8 were a carpenter, then x_8 is taking a plane, and that for all x_8, x_8 will not take a plane we can infer that for all x_8, x_8 is not a carpenter. Finally, from the fact that there is at least one x_8 for which if x_8 were sad, then x_8 is a carpenter, and that for all x_8, x_8 is not a carpenter we can infer that there is at least one x_8 for which x_8 is not sad, which contradicts that For all x_8, x_8 is sad. Therefore, the answer is no.