It is customary for big groups to enjoy simple dishes together as 20 .
答案：(C) a joyful social activity
語意「大家一起享用簡單的菜餚，作為一種『歡樂的社交活動』」，a joyful social activity 符合，呼應全文強調點心是一種體驗而非單純食物；a widely known delicacy（廣為人知的美食，強調食物本身而非社交面向）、an intimate romantic dinner（跟「大群人」矛盾）、an amazing local cuisine（同樣偏向食物本身）都不如這個選項精確呼應文章主旨。
整篇都在談點心這種食物，你的注意力自然會停在「哪一個選項最能形容點心好吃」，於是在 delicacy（珍饈）與 cuisine（菜系）之間猶豫。但這一題問的根本不是點心好不好吃，而是大家聚在一起吃點心這件事算什麼。方向一旦看錯，四個選項會覺得三個都可以。
先看句子結構：It is customary for big groups to enjoy simple dishes together as ___. 主詞是 big groups「一大群人」，動詞是 enjoy... together「一起享用」，as 在這裡是介系詞「作為」。所以空格要填的是「一群人一起吃飯」這個行為的定位，不是食物的評價。再往下看文章最後一句：Ultimately, dim sum—the food—is only a small part of the dim sum experience.（說到底，點心這項食物只是整個飲茶體驗的一小部分）——作者把「食物」和「體驗」明白切開，答案當然要落在體驗那一邊。有三個選項在講食物、只有一個在講活動，這種「三同一異」的排列本身就是提示。
a widely known delicacy（廣為人知的珍饈）與 an amazing local cuisine（了不起的地方菜系）都是在評價食物，正好被最後一句否定掉；順帶分清這兩個字：delicacy 指某一樣珍稀精緻的食物，cuisine 指某地區的整套烹調風格（如 Cantonese cuisine 粵菜），不可互換。an intimate romantic dinner（親密的浪漫晚餐）則與主詞 big groups 語意矛盾——浪漫晚餐通常是兩個人的事，主詞就把它刷掉了。
It is customary (for sb) to V（（某人）習慣……、依慣例……）、customary practice（慣例）、enjoy sth together（一起享用）、as ＋ 名詞（作為……）、a social activity／gathering／event（社交活動／聚會）、local cuisine（地方菜）、a rare delicacy（珍稀美食）。
The history of dim sum stretches back to the early days of the Silk Road, an ancient network of trade routes connecting the East and the West. Those who traveled along the routes through China needed places to rest. Teahouses thus sprang up to 16 the weary travelers, offering them a cup of tea to help them regain energy. But the culinary art of dim sum 17 , for it was considered inappropriate to pair tea with food.
Centuries later, the ability of tea to aid in digestion finally became known. Teahouse owners therefore began providing bite-sized snacks as an accompaniment, and the tradition of these Cantonese delicacies was born.
Dim sum is more than just an example of Chinese cuisine. It is 18 an enjoyable dining experience that can span hours. The small portions were designed to merely "touch the heart," as the name literally means, and 19 were first enjoyed as snacks. The small size allows the customer to order a great variety of dishes, creating a banquet of different tastes and flavors. It is customary for big groups to enjoy simple dishes together as 20 . Ultimately, dim sum—the food—is only a small part of the dim sum experience.