Consider the following premises. For all z, z is a lawyer if and only if z will play squash. For all z, z is a lawyer if and only if z will play squash. Can we infer the following from them? If Thomas were a lawyer, then Thomas is playing squash.
 From the fact that for all z, z is a lawyer if and only if z will play squash we can infer that for all z, if z plays squash, then z is a lawyer. From the fact that for all z, z is a lawyer if and only if z will play squash we can infer that for all z, if z were a lawyer, then z is playing squash. From the fact that for all z, if z plays squash, then z is a lawyer, and that for all z, if z were a lawyer, then z is playing squash we can infer that for all z, z will play squash if and only if z is a lawyer. From the fact that for all z, z will play squash if and only if z is a lawyer we can infer that Thomas is playing squash if and only if Thomas is a lawyer. Finally, from the fact that Thomas is playing squash if and only if Thomas is a lawyer we can infer that if Thomas were a lawyer, then Thomas is playing squash. Therefore, the answer is yes.