What does "here comes something" mean? Can I say "An airplane comes here" or "here airplane comes" instead?
"Here comes something" means that something is approaching or getting closer. In English, the general sentence pattern is subject + verb + object. "Here comes an airplane" follows this pattern, with the object placed right after the verb "come". It would not sound as grammatically correct to say "an airplane comes here" or "here an airplane comes", because in both of these sentences, the verb is placed after the object. There are some exceptions to this grammar rule, but in general it is useful to follow this sentence pattern.