Передайте предложения косвенной речью, обратите внимание на модальные глаголы.

1) "I cannot come." - Mary explained that …
2) "Claire must rest." - The doctor said…
3) "You needn't change your shoes in
our house." - She reminded me that …
4) "I would buy it." - She said…

5) Mike: "I must arrange a couple of things." - Mike explained that…
6) "We must go skiing in winter." - He said that…

Mary explained that she couldn't come.The doctor said that Claire might rest.She reminded me that I didn't need to change shoes in the house.She said that she would buy that.Mike explained that he might arrange a couple of things.He said that we might go skiing in winter.