If you misintroduce someone, you could try saying something like, 'I apologize....He/she is Mr/Ms Thakur'. Remember that it is better to misintroduce someone than not to introduce at all.

nanometric scale

a lentil salad

I am truly sorry that I cannot accompany you in your ride this morning, owing to a violent pain in my face, arising from a wart to which I by medical advice applied a caustic. Whether I put too much, I do not know, but the consequence is, that not only I have been put to some pain, but the peccant part and its immediate environ are as black as if the printer's devil had marked me for an author.