To look after someone or something

A phrasal verb is composed of two (sometimes three) words. This one (look after) is composed of two words in the following order:

1. Verb (a word that describes an action, like 'run,' or 'speak.') = look
2. Preposition (a word used before a noun, like 'on,' or 'into.') = after

Prepositions go before a noun, that's why they're called pre + positions. We say look after someone or look into the matter, or do without a holiday. Here's something very important: Because the preposition goes before a noun, not after a noun, we say:

1. Who'll look after the children? (not look the children after). The noun 'children' cannot come before the preposition 'after.'
2. We can do without caviar this week (not do caviar without). The noun 'caviar' cannot come before the preposition 'without.'