The formation of noun phrases using ‘my’ or ‘your’ + superlative adjective + noun in English grammar.
A noun phrase acts as a noun and describes a noun, while a superlative adjective compares a noun to the rest of a group and indicates the highest degree of a quality.
For instance, in the sentence “That’s your biggest mistake,” ‘your biggest mistake’ is a noun phrase where ‘biggest’ is the superlative adjective and ‘mistake’ is the noun.
The text also provides examples of such phrases commonly used in English, such as “your best bet,” “my best friend,” “your best friend,” and so on. It mentions that using A2 vocabulary or higher in this structure will probably be considered B1 context.