I can’t seem to suggest that he cleaned the floor besides “in a perfunctory

manner”.

I would say “he is a teacher, and she is a teacher”, “How do I explain to myself this? What do you mean by “and what is she?” I

don’t think there is any need to repeat the pronoun in the answer. She is a teacher too, is quite sufficient.

How can I soften your refusal? Presumably you had asked your friend to do something with you that evening; it would not have been very polite of them to say bluntly “I can’t – I’m staying at home.” Yes, you can say “I’m afraid I’ll be late today” (note the capital I and the apostrophes), meaning “I’m sorry that I have to tell you this, but…”