Consider the following premises. If David were curious, then Elisabeth is a mechanic. If Sarah plays squash, then David is curious. For all x_14, if x_14 writes a letter, then x_14 is curious. David is writing a letter or Sarah is playing squash. Can we infer the following from them? Elisabeth is a mechanic.
 From the fact that for all x_14, if x_14 writes a letter, then x_14 is curious we can infer that if David writes a letter, then David is curious. From the fact that if David writes a letter, then David is curious, that if Sarah plays squash, then David is curious, and that David is writing a letter or Sarah is playing squash we can infer that David is curious. Finally, from the fact that if David were curious, then Elisabeth is a mechanic, and that David is curious we can infer that Elisabeth is a mechanic. Therefore, the answer is yes.