Task: Explanation
Input (English): Question: Joe noticed that the humidity inside the greenhouse was getting very high, so he opened the roof to let cooler air inside. Thus, when the water potential gradient across the inside and outside of the leaf becomes equal, the rate of transpiration will 
 Answer: decrease.
Output (English): As humidity increases, the water potential gradient across the inside and outside the leaf become more equal, and so the rate of transpiration decreases.