in a shape of，表示以一种……的形状，in the shape of，表示形状为……，例如：

1.Look, it is in a shape of octagon and it has eight extending eaves, with yellow glazed tiles on the roofs.看，它是八角形，它有八个突出的屋檐。屋顶上是黄色的瓦片。

2.It is in the shape of a whale.它是鲸鱼的形状。

3.The Royal Crescent is a row of 30 houses in the shape of crescent.皇家新月楼由30座排成一排的房子组成，排列形状似一弯新月。