Tense particles

Firstly, tenses in Vietnamese are kept simple; that is, it is rare to hear the combination of tense particles in order to produce a complex tense such as the tenses we use in Indo-European languages.

You can combine tense particles and people will probably understand you, but it is not the done thing (in my experience thus far) and might get some laughs and raised eyebrows!

(I continue to construct complex tenses when speaking Vietnamese and haven't yet been told to stop.)

common past	rồi	"already" — used all the time, it casts anything into the past
simple past	đã	"did"
simple future	sẽ	"will"
recent past	vừa	literally "just"
recent past	mới	literally "new"
extremely recent	vừa mới	"just now"
used to do	từng	could be once or many times or regularly
not yet	chưa	"yet", "not yet". Not a tense like how we conceive of tenses, but it does place the sentence/question in time.