Mooncakes are a staple. It's a round pastry and there are many different fillings.
月餅是必須的。它是種圓圓的點心，有很多不同的餡料。

Staple
基本，必須

Turkey is a staple at most traditional Thanksgiving dinner.
大多數傳統感恩節晚餐里火雞都是必須的。

Music is a staple at parties.
聚會中音樂是必須的。

Mooncakes are a staple.
這里Mooncakes表示一類，這一類東西都必不可缺。

Fruits are an important part of a healthy diet.
水果是健康飲食中不可或缺的一部分。

Vitamins are a waste of money.
維他命就是在浪費錢。

Staple
訂書針

Stapler
訂書機

It's a...and there are...
如何描述一種食物

a. It's a round pastry and there are many different fillings.

round pastry
圓圓的點心

filling
餡料

Dim sum
點心/早茶

b. Dim sum is a Cantonese style cuisine and there are many steamed dishes like barbecue pork buns and shrimp dumplings.
點心是一種廣式菜，里面包括很多小吃比如叉燒包和蝦餃。

c. Hotpot is a pot of soup and you cook meats and veggies in it.
火鍋就是一鍋湯你可以在里面涮肉和菜。