twins
Zwillinge is the German word for twins. It is a plural noun and refers to two individuals who are born at the same birth. It is used in the same context as twins in English.
The twins are playing in the garden.
This sentence is utilizing the plural noun 'Zwillinge' to refer to 'twins'. As the sentence indicates an ongoing action in present time ('are playing'), the present tense of the verb 'spielen' ('to play') is used.
The twins have a birthday.
In this example, the plural noun 'Zwillinge' ('twins') is again used. The verb 'haben' ('to have') is used to denote possession of a particular occasion - a birthday. Note, birthdays in German are expressed differently than in English, i.e., 'have' instead of 'is'.
The twins looked identical.
This sentence utilises the verb 'sahen' ('looked') in past tense to describe a condition of the 'Zwillinge' ('twins'). In this context, 'aus' is a separable verb prefix combined with 'sehen' to mean 'look' in English.