Ⅰ. difficult “困難”多指智力上的困難。一般可與hard代換。但比它程度要大。如：
① The question is difficult to answer.
Ⅱ. hard “困難”多指體力上的困難。如：
①Some of the apples are hard to reach.
① The question is difficult to answer.
Ⅱ. hard “困難”多指體力上的困難。如：
①Some of the apples are hard to reach.