Prepositions form a closed word class, although there are also certain phrases that serve as prepositions, such as "in front of". A single preposition may have a variety of meanings, often including temporal, spatial and abstract. Many words that are prepositions can also serve as adverbs. Examples of common English prepositions (including phrasal instances) are "of", "in", "on", "over", "under", "to", "from", "with", "in front of", "behind", "opposite", "by", "before", "after", "during", "through", "in spite of" or "despite", "between", "among", etc.