Using this Cantonese particle to indicate past tense I ran across this 'conversation piece' in a Cantonese study material.
填好地址未？ 
填好晒。 
郵票貼好未？ 
貼好咗啦。
I found the usage of 晒 strange, because 填好 already indicated the action is done. The same is true with 貼好咗啦. 貼好 already indicates the action has been done, and yet there is an additional 咗. Is this all right? I would just use 啦, just to break the 'awkwardness' of having two characters only.
Please explain.
晒 as a verb particle here indicate - 'All; completely'
Example: 走晒 (all left); 死晒 (all dead; completely dead); 冇晒 (all gone)
填好晒 =  finished filling it all
The phrase 貼好  (finished sticking on) indicated the verb is completed already
Add aspect marker 咗 after 貼好 and say &quot;貼好(咗)&quot; reinforce the 'completed' aspect. Make it sound more asserting.
You can add the final particle 啦 to 貼好 (finished sticking on), 貼咗 (already stuck on) and 貼好咗 (finished sticking on already)
The final particle (modal particle) 啦 serves to express different emotion depend on the context and tone
Example: 貼好(咗啦)

If you stretch the 啦 sound, it implies announcement

If you strengthen the 啦 sound, it implies anger

If you lower the 啦 sound, it implies annoyance


Notice: 貼好(咗) only indicates it is a 'completed verb'. It doesn't mean it is a 'verb in past tense' because Chinese doesn't use tenses.
In this context, adding the final particle 啦 does suggest the action was in the past. Otherwise, it wouldn't affect your mood