The grammar you actually need (and what you can ignore)

Grammar books are written to be complete, not to be useful. They give equal weight to the present tense and to the future perfect continuous, though one appears in every sentence you will ever say and the other appears roughly never.

Here is the order that matters if the goal is speaking.

The four that carry everything

1. Present simple — for facts and habits.

I work at a school. She lives in Zirakpur. We start at nine.

2. Present continuous — for right now.

I am cooking. She is sleeping. They are waiting outside.

3. Past simple — for finished things.

I went. She called. We finished it yesterday.

4. Going to / will — for what's ahead.

I am going to call her. I will send it tomorrow.

That is it. Those four cover the overwhelming majority of everyday speech. A person who uses only these, accurately and confidently, sounds fluent.

Worth adding next

Present perfect, because Indian speakers often use past simple where English uses it:

I have been here for two years. (not: I am here since two years.)

Can / could / should, because polite requests run on them:

Could you send me the address? Should I call him?

Questions, properly formed — many learners can answer but not ask:

Where is the meeting? When did she call? Why are they waiting?

What you can genuinely postpone

• Future perfect continuous (I will have been working) — almost never spoken
• Third conditional (If I had known, I would have gone) — useful eventually, not early
• Passive voice — understand it, don't chase it
• Most of the "advanced" tenses in the back of the book

None of these will stop a conversation. Being unable to form a question will.

The mistake worth avoiding

Studying grammar as a subject rather than a tool. People spend months on exercises, score well, and still cannot speak — because written exercises practise recognition, and speaking needs production.

Learn a structure, then use it out loud twenty times in sentences about your own life. That is worth more than a chapter of fill-in-the-blanks.

And the real secret

Native speakers make grammar mistakes constantly. What they do not do is stop mid-sentence to fix them.

Accuracy comes from repetition, not from worrying. Speak first, tidy later.