这些古老的传统构成了他们文化身份的核心。

These ancient traditions ___form the core of their cultural identity.

他广泛的研究构成了整篇论文的基础。

His extensive research ___forms the foundation of the entire thesis.

清晨的薄雾在山谷上形成了一层精致的薄纱。

The early morning mist had ___formed a delicate veil over the valley.