someone和some one的区别主要是：
someone：某人，有人，但不知道是谁；
some one：有人(某个，某人)，知道此人，但不认识。
someone例句：
He found someone on him.
他发现有人在跟踪他。
Someone knocked on the wall and he knocked back.
有人敲了一下墙壁，他应声回敲。
I had only danced with Mary about three minutes when someone cut in.
我和玛丽刚刚跳了大约三分钟的舞，就有人来截舞。
Someone ripped off my wallet.
有人偷了我的钱夹子。
Someone came out with a most useful suggestion.
有人提出了一个非常有益的建议。
some one例句：
Once he paused to salute some one in the crowd.
一次，他停了嘴，向听众中的一个人打招呼。
Now, suppose some one to place an iron ball on the table; then will this ball run straightway towards the magnet.
这时假设有人在桌子上摆一个铁球，那么这个铁球立刻就会朝着磁铁的方向滚动过去。
She was roused from her seat, and her reflections, by some one's approach; and before she could strike into another path, she was overtaken by Wickham.
这时已经有人走近前来，打断了她的深思，使她从座位上站起来；她刚要从另一条小径过去，只见韦翰却赶了上来。
It was not long before some one knocked at the house-door and called, open the door, dear children, your mother is here, and has brought something back with her for each of you.
没过多久，有人敲门，而且大声说：“开门哪，我的好孩子。你们的妈妈回来了，还给你们每个人带来了一点东西。”
Some one left a cake on our front porch.
有人在我们的门廊上留下了一块蛋糕。