示范答案：
Laughter is often a short-term response to a situation, whereas happiness is a more longterm thing. One can laugh at a situation for a few moments, but at the same time one can be very unhappy. One can also be happy without needing to laugh. A son or daughter has gained a good job（1） in a foreign country. You are happy because they have got what they were looking for and you share that happiness, yet, at the same time laughter here would be out of place — it would add nothing. You might be sad that they will be living far from you.
