。
The boy next door often comes home late.
Literal
Next [at-に] live-ている boy [topic-は] late come-home things-[subject-が] often-ことが多い.
~ことが多い ('often, frequently,' literally 'there are many instances of X') is a common way to express frequency of a behavior or event. Less direct than よく ('often') — puts the frequency in object-like structure. Descriptive of a habit.