1. You didn't see him, is it?
· You didn’t see him, did you?
2. When you would like to go?
· When would you like to go?
3. That man he is tall.
· That man is tall.
4. Her jewelleries were stolen.
· Her jewelry was stolen
5. I am understanding it now.
· I understand now.
6. They two very good friends.
· Those two are very good friends.
7. Sushila is extremely a lazy girl.
· Sushila is an extremely lazy girl.
8. When you leaving?
· When are you leaving?
If you look at the first sentence the mistake was in the consistence of verb tense and person. In the second part of the sentence "it" is used instead of "you", and "is" is used instead of "did". You can hear that "is it" sounds like an incorrect ending to the sentence.
In the second sentence you and would is placed in the wrong order. The pronoun is placed before the verb, and in this sentence that does not make sense. It sounds much better if you say "when would you".
In the third sentence there are two subjects right after one another, which is not logical. There is no need to say that "that man" is a "he" or that "he" is "a man". The sentence would be correct if you said "that man is tall" or "he is tall"
In the fourth sentence the mistake is simply that it uses a word that doesn't exist in the English vocabulary. You can't use the word "jewelleries", but if you exchange it with the word "jewelry" the sentence makes perfect sense. The reason is that the word "jewelry" is both simple and plural.
