The two dimples on his cheeks are his biggest facial characteristic. characteristic就是个普通的名词,没什么句型. 你可以说one's main characteristc is...或sth.is one's characteristic.
脸上的两个酒窝是他面部最大的特征。 Face two dimples is his face the greatest feature of the. One of the characteristic features of this technique is its replicability. 这种技术的独特的特征之一就是它的可重复性。