i want to ask a question about how to know the suitable tense which we have to put in the sentence . how to know if we have to put present simple or present continues ? how we can know if we have to put past simple or past continuies ?
Your question is so general that it requires a general answer.

The simple tenses tend to express habits or completed actions or events.
The continuous tenses tend to express on-going activities.

It is much more complicated than that, of course, and many books have been written on the subject of tense in English!

If you have a specific sentence or two which are troubling you in this way, post them and we can probably provide more help in that way.

Emotion: smile
Thank you for your help claifjim .

I just want to know the differences between the sentences to can know exactly which tense i can use in any sentence . May be in the exam they give to me sentence and they what me to correct the verb in the right sentence , the problem here will be how to know the right tense and the suitable tense for the sentence .

And thank you again for your helpEmotion: smile