Consider the following premises. Karen is sad. If Mary drinks water, then Karen is sad. Mary is drinking water or Karen is not sad. Can we infer the following from them? Mary is drinking water.
 From the fact that Mary is drinking water or Karen is not sad we can infer that if Karen were sad, then Mary is drinking water. From the fact that if Karen were sad, then Mary is drinking water, and that if Mary drinks water, then Karen is sad we can infer that Karen is sad if and only if Mary is drinking water. From the fact that Karen is sad if and only if Mary is drinking water we can infer that if Karen were sad, then Mary is drinking water. Finally, from the fact that if Karen were sad, then Mary is drinking water, and that Karen is sad we can infer that Mary is drinking water. Therefore, the answer is yes.