(1) About seven out of ten people released from prison end up in prison again sooner or later.

参考翻译：被释放出狱的10个人当中大约有7个人迟早还会再次进监狱。

end up的意思是“以……告终”“最后……”“到头来还是……”，比如：

If you continue to steal, you’ll end up in prison. 你要是继续行窃，你会坐牢的。

There was a terrible scene and Jayne ended up in tears. 发了很大的火，简结果哭了。

I really wanted to work in television but I ended up in radio, which is the next best thing. 我确实想做电视工作，最后到了电台工作，这是仅次于它的最好的工作。

(2) What sort of height?

参考翻译：大约多高？

sort of 有个用法就是大致情况。如：

That's the sort of price I was hoping to pay. 我希望出的差不多就是那样的价格。

What sort of time were you thinking of starting? 你大概想要什么时候开始？

(3) He had some cowboy boots, black leather, with high sides.

参考翻译：他穿了双牛仔靴，黑色皮革的，靴统很高。

这里的 with high sides 是指靴统很高。