1. The clams we found on the beach were equivalve, with both sides of their shells perfectly matched.

我们在海滩上找到的蛤蜊是两边贝壳对称的，贝壳的两侧完美匹配。

2. The equivalve nature of the bivalve shells is an important characteristic for their classification.

对于双壳类贝壳来说，两边贝壳对称的特性是它们分类的重要特征。