I think I'll sleep in this morning, but I'll be at school this afternoon.
I think I might sleep all morning, and just go to school in the afternoon.
ーI think I'll sleep in this morning, but I'll be at school this afternoon.
「午前中は寝て、午後から学校に行くよ」
to sleep in this morning で「午前中はゆっくり寝る・遅くまで寝る」
ーI think I might sleep all morning, and just go to school in the afternoon.
「午前中はずっと寝て、午後だけ学校に行くよ」
to sleep all morning で「午前中はずっと寝る」
ご参考まで！
カナダ 
