Sentences containing conditional clauses like 'if' , 'unless and 'provide that' are called conditional sentences. There are four types and express four types of meaning.

$\star{ \text{ \: Type \: zero}} :$ It always expresses real and possible.

If + simple present : simple present ( for scientific facts )

Example: If water is boiled , it changes into water vapour.

If + simple present : Imperative

Example: If you want to win, play fair.

$\star{ \text{ \: Type \: one}}$ : It expresses possible situation in the present or future.

If + simple present : will / shall / can / may / must + V¹

Example : I shall play football if I get chance.

$\star{ \text{ \: Type \: two}}$ : It expresses doubtful situation / hypothetical condition in the present or future

If + simple past : would / should / could / might + v¹

Example : If I were you , I would never accept the proposal.

Note: ' Be' verb in if clause always becomes ' were ' ( only in conditional sentence type two)

$\star{ \: \text{ \: Type \: three}}$ : It expresses regret / unfulfilled situation in the past.

If + past perfect : would / should / could / might + have + v³

Example : He would have helped you if you had asked him.

$\star { \: \text{ Unless : if \: not}}$

' Unless ' has the similar structure like ' if ' but it gives negative / situational meaning.

Example : She wouldn't learn much unless she worked harder.

$\star{ \text{ \: Provided \: that : if}}$

' Provided that ' functions like ' if ".

Example: Provided that you were a teacher , what would you do?

$\star{ \text{ \: Inversion}}$

The auxiliary verb of conditional sentence type two and three can be fronted in place of ' if'

Example: Were I a bird , I would fly.

Hope I helped!

Best wishes! :D

~ $\sf{ TheAnimeGirl}$

5 0

2 years ago