last month
fixed phr..fixed phr.. The month that came just before the current one.
fixed phr.. A fixed temporal expression referring to the calendar month immediately preceding the present one, used as a noun phrase or adverbially.
I saw that movie last month.
We finished the project last month, just before the new quarter started.
The policy changes announced last month have already begun to affect international trade agreements and market stability.
This phrase is used without a preposition like 'in' or 'on' when it refers to time.
Point out that 'last month' (like 'last week' or 'next year') functions as an adverb of time and does not need a preposition.
We paid the bill on last month.We paid the bill last month.Phrases with 'last', 'next', 'this', and 'every' do not use prepositions like 'in', 'on', or 'at' to talk about time.