переделать в косвенную речь

KATE said to me I' ve finished  your book. it was very interesting

the teacher said The Earth goes round the moon

The British Prime Minister said Russia is a great country

My friend asked me Should i come to your place or stay at home

Kate said to me that she had finished my book. and that it had been very interesting

the teacher said that the Earth went round the moon. (это не правда, Земля вращается вокруг Солнца, поэтому делаем шаг назад)

The British Prime Minister said that Russia was/is a great country. Если в предложении говорится о непреложной истине, то не надо делать шаг назад. Действительно ли в предложении непреложная истина решать Вам. 

My friend asked me if I should come to your place or to stay at home.