The apple is red. 苹果是红色的 It is John’s apple. 这是John的苹果 I give John the apple. 我给John苹果 We give him the apple. 我给他这个苹果 He gives it to John. 他把它给了John She gives it to him. 她把它给了他 Is the apple red? 苹果是红色的吗？ The apples are red. 这些苹果是红色的 I must give it to him. 我必须把它给他 I want to give it to her. 我想把它给她 I’m going to know tomorrow. 我明天要知道 I have eaten the apple. 我已经吃了苹果 I can’t eat the apple. 我不能吃苹果

The apple is red. 这是红苹果。 It is John’s apple. 这苹果是约翰的。 I give John the apple. 我把这苹果给了约翰。 We give him the apple. 我们把这苹果给了约翰 He gives it to John. 他把这苹果给了约翰。 She gives it to him. 她把那东西给了约翰。 Is the apple red? 这苹果是红的吗？ The apples are red. 这些是红苹果。 I must give it to him. 我非得把这苹果给她。 I want to give it to her. 我想把这苹果给她。 I’m going to know tomorrow. 我明天研究。 I have eaten the apple.我把那苹果吃了。 I can’t eat the apple.这苹果我吃不了。

The apple is red. 这个苹果是红色的。 It is John’s apple. 这是约翰的苹果。 I give John the apple. 我把这个苹果给了约翰。 We give him the apple. 我们给了他一个苹果。 He gives it to John. 他把这个苹果给了约翰。 She gives it to him. 她把这个苹果给了他。 Is the apple red? 这个苹果是红色的吗？ The apples are red. 这些苹果是红色的。 I must give it to him. 我必须给他这个苹果。 I want to give it to her. 我想把这个苹果给她。 I’m going to know tomorrow. 明天我就知道会把这个苹果给谁的。 I have eaten the apple. 我已经吃掉了一个苹果。 I can’t eat the apple. 我不能再吃这个苹果了。 It is an English game to play with we/he/she/it/I/John/apple as well as the tense, but in Mandarin, we have no such strong sense on the them.

这个苹果是红色的 这是John的苹果 我给了John这个苹果 我们给了他这个苹果 他把它（它：in here means 苹果)给了John 她把它（means 苹果）给了他 这个苹果是红色的吗？ 这些苹果是红色的 我必须把它给他（它means 苹果） 我想把它（它means 苹果）给她 我明天就知道了 我吃了一个苹果 我不能吃苹果

The only problem with the translations involving "it" is, it should not be translated into Chinese. You can only use "it" if the subject from a previous sentence already established what "it" was. Most of the time, based on my research, "it" can be omitted. How to say, it's hot? Simply say, "hot." You can substitute This or that in place of "it" which is used more often. The translations you were given did translate "it", but since "it", "he", "she", "her", and "him" are all pronounced the same way, it could be confusing to have a sentence saying, he and she and it ... One last thing, this and that should be used in a sentence if the other person can see what "this or that" is ... watch this youtube video https://www.youtube.com/watch?v=zfvhaRKCU8c&index=19&list=PLSfmcHo60bTxQNUUhZBHf3hkaEsNqfi_l