没有人说"它是约翰的苹果"的! 那是英语的说法。你可能已经发现，中文跟英语原来是两种不同的语言来的，英国人和中国人不是同一个民族来的，用英语语法学中文就是大傻瓜， 你不会在篮球场中学游泳吧？ 我们说: 那是约翰的苹果; 这是约翰的苹果。至于用"这些"还是"那些"，就得看情景。 学中文的时候，记住把英语扔掉，当自己不会英语。靠翻译来学中文，是最糟糕的方法。

THE is a word that exists in Eng. And in order to understand why a "the" word must be in a sentence (eg.[the apple on the table] ), we use “这/那” to make it clear, at least for us. 这 = this 那=that 这些=these 哪些=those A sentence like [ The apple is on the table. ], in Eng, if the apple is near to you, you can say [ this], right? And if the apple is far from you, you can say "that apple (is on the table)" instead. In Chinese, we just make the " distance " more specific. That's all. :) For "IT" word, it depends: If [ it ] is belong to [ it ] in " I you he she it we they ", it's “它”。 if it in a sentence like " It's good to see you"/ "It's my pleasure ( to do so). " / or other "it's (adj.) to do something" etc, in which "it" actually plays no parts, in Chinese "it" as well doesn't need to translate. : )

In Chinese, 1. “it” used to indicate object except human being. Such as sun, tree, lion, etc. It=它 2. when object is close to the speaker, it = 这个 3. when object is away from the speaker, it= 那个 The apples are red. 那/这些苹果是红色的 (plural) The apple is red 那/这个苹果是红色的 （singular） “那些苹果是红色” is wrong. “的” can not be omitted.

Ben讲的是对的，不要用英语的语法来学习汉语。 就算可以理解成this＝这，that＝那，these＝这些，those＝那些，it＝它。便事实上，汉语说成了并不会按照英语this，that，these, those,　it的使用方式去使用“这、那、这些、那些，它”。 the apples既可以是这些苹果，也可以是那些苹果，还可以是这苹果，那苹果。不同的场合用不同的方式表达。 It's raining.要说成“在下雨”或“天在下雨”，这里的it就不是“它”。汉语不会说成“它在下雨”。

I think it's also possible to say: 那个苹果是John的。