The sentences in your last post sound odd to me, Hoa Thai
"We have sold out our inventory." This sounds a little awkward to me. Here are some alternatives:
We have sold all of our inventory (of red shirts).
Our inventory (of red shirts) is sold out.
Our red shirts are sold out.
We are (all/completely) sold out (of red shirts).
"We have sold out all our stock of T-shirts." I really don't like this sentence at all -- it sounds very awkward to me. The word 'all' would typically be used for extra emphasis and like the word 'completely' (i.e.as an adverb) in sentences using a structure similar to 'We are (all) sold out'. However, when sell out is used as a verb, then it only seems redundant to say "We sold out all of our stock of T-shirts". Use either 'out' of 'all of', but not both.
"We have sold out a development of 110 units." (Sorry, but I'm not sure I understand this sentence. Did you read it somewhere? Does it refer to a housing development?)