What would you buy first if you (win) a million pounds. (correct)

الجواب...
won

What.... ( you buy) if you won a million pounds. ( correct)

What would you buy......

Zero conditional..

If + present simple, present simple.

Present simple if present simple

How long.... في الوحدة ااخامسة

How long have you +p. p...?

مع المضارع التام البسيط... عند وجود الافعال التالية...
Know, be, hear, understand

How long have been a pilot?

How long have you known him?

مثال مهم..
You meet a pilot. You ask( how long /be)

How long have you been a pilot?

عند عدم وجود فاعل تجيب الضمير you

How long have you been +ing?

مع المضارع التام المستمر.. نتبع هذه الطريقة في تكوين جملة
You have a friend who is learning English. ( How long/ learn)

How long have you been learning English?

been gone...

تاتي في الاختيارات

I have been to London.

Have you ever been to London?