Sentence:  There are two non-finite forms in Swedish, the infinitive and the <WSD>supine</WSD>. ... The <WSD>supine</WSD> has two basic allomorphs: "-t" (weak verbs) and "-it" (strong verbs). ... The <WSD>supine</WSD> verb phrase serves as complement of the perfect auxiliary "ha" 'have' ("hon hade bundit honom") which can be deleted, though, in subordinate clauses ("eftersom hon [hade] bundit honom" 'since she had bound him'). (The <WSD>supine</WSD> has existed as a morphologically distinct category in standard Swedish language at least since the 19th c.; cf. art. 155.) 
Meaning of the word marked with <WSD> tags:  In Swedish: a verb form that combines with an inflection of (ha) to form the present perfect and pluperfect tenses.