其中的 come 表示某事物（尤其指某产品）的呈现形式（包括规格、颜色、形状、款式、浓度等）。网友的句子意思是：

Xi’an’s dumplings come in many shapes, colors and sizes.

西安饺子的形状、颜色和大小都有很多种。

更多例句如：

Shoes come in many shapes and sizes. 鞋子有多种样式和尺码。

The pieces came in many different sizes and shapes. 零部件大小不一、形状各异。

These nails come in three standard sizes. 这些钉子有三种普通规格。

The shirts come in three sizes: small, medium, and large. 这些衬衣有三个尺码: 小号、中号和大号。

Few people realise that ladybirds come in different colours. 人们不知，瓢虫有不同的颜色。

The shirts come in five different colours—just take your pick. 这种衬衫有五种不同的颜色——你随便挑吧。

The milkshakes come in different consistencies. 奶昔饮料浓度不一。