那只绿褐色的黑脸小猴子是只非洲长尾猴。

That small greenish-brown monkey with a black face is a ___vervet.

长尾黑颚猴的社交行为非常复杂，它们会互相梳理毛发。

The ___vervet's social behavior is quite complex, as they groom each other.