Marginal effect: When consumers add a unit of consumer goods one by one, the unit utility brought by them gradually decreases. According to the above definitions, Which of the following are marginal effects:. ['Hong Mou ventured into the sea and made 600,000 in the first year, 200,000 in the second year, and lost money in the third year.', 'Cheng was very curious when he took the child to the museum for the first time, and the child was very happy when he went there the second time, but when he went to the fifth and sixth time, the child was a little tired.', 'Guo is a senior philatelist enthusiast. The last day of his collection of baby stamps was finally collected the day before yesterday. The excitement was even happier than hugging his grandson.', 'Fan invited a friend to dinner, and the wine went down one bottle at a time.']