Consider the following premises. If Robert doesn't take a plane, then William is an astronaut. Charles is curious. If William were an astronaut, then Mary is drinking water. If Robert takes a plane, then it is not cold. Charles is curious if and only if it is cold. Can we infer the following from them? Mary is drinking water.
 From the fact that Charles is curious if and only if it is cold we can infer that if Charles were curious, then it is cold. From the fact that if Charles were curious, then it is cold, and that Charles is curious we can infer that it is cold. From the fact that if Robert takes a plane, then it is not cold, and that it is cold we can infer that Robert is not taking a plane. From the fact that if Robert doesn't take a plane, then William is an astronaut, and that if William were an astronaut, then Mary is drinking water we can infer that if Robert doesn't take a plane, then Mary is drinking water. Finally, from the fact that if Robert doesn't take a plane, then Mary is drinking water, and that Robert is not taking a plane we can infer that Mary is drinking water. Therefore, the answer is yes.