Adults tend more to fit the second type. Generally speaking, the harder students study, the less likely it is that they will forget. After going through a period without contact with the language, their ability grows rusty, just as one's fingers feel tight when trying to type or play the piano after not having typed or played for a while.
至於成人，通常得視學習的熟練程度，「愈辛苦學的，愈不易忘」，鄭昭明說，即使忘記了也只是一時生疏，這就好像久不彈鋼琴或久不打字時，手指有些僵硬，但只是「暫時壓抑」，並不代表就不會了。