The categories of mood, tense, and or voice may be absent from non-finite verb forms in some languages.
[2] Because English lacks most inflectional morphology, the finite and the non-finite forms of a verb may appear the same in a given context.
In languages like English that have little inflectional morphology, certain finite and non-finite forms of a given verb are often identical, e.g.
The following table illustrates such environments: English participles can be divided along two lines: according to aspect (progressive vs. perfect/perfective) and voice (active vs. passive).
They can appear in periphrastic verb catenae, when they help form the main predicate of a clause, as is illustrated with the trees below.
The form of a given perfect or passive participle is strongly influenced by the status of the verb at hand.
The perfect and passive participles of weak verbs, in contrast, are regular and are formed with the suffix -ed (e.g. fixed, supported, opened).
Gerunds typically appear as subject or object noun phrases or even as the object of a preposition: Often, distinguishing between a gerund and a progressive active participle is not easy in English, and there is no clear boundary between the two non-finite verb forms.
For an overview of dependency grammar structure in modern linguistic analysis, three example sentences are shown.