na
(particle equivalent to 啊 after noun ending in -n)
na
sentence-final particle (abbr. for 呢啊[ne5 a5] or variant of 哪[na5])
zài na r
(adverbial expression indicating that the attention of the subject of the verb is focused on what they are doing, not distracted by anything else)
just ...ing (and nothing else)
tiān na
Good gracious!
For goodness sake!