Hypothetical sentences source busyteacher.org

2. 
 Conditional sentences express a condition
(if…) and the consequence of the condition.
 The consequence can be expressed before or
after the condition:
  If you come to Canada, we can visit
Vancouver = we can visit Vancouver if you
come to Canada.
 Note: if the condition comes first, a comma is
used. If the consequence comes first, no
comma is used.

3.  There are four (4) basic types of
conditional clauses:
 0 - zero 1: for what IS always true
 0 – zero 2: what WAS always true
 1ST : what will be true = REAL IN THE
FUTURE
 2ND: UNREAL IN THE PRESENT
 3RD : UNREAL IN THE PAST

4.  In ZERO 1 clauses we can replace IF with
WHEN/WHENEVER
 If (When/Whenever) + Present Simple
Present Simple
 If (When/Whenever) I go to bed late, I
have a headache in the morning.
 If (When/Whenever it rains, the streets
are wet. = The streets are wet if
(When/whenever) it rains.

5.  In ZERO 2 clauses : IF = WHEN =
WHENEVER
 If (When/Whenever) + Past Simple Past
Simple
 If (When/Whenever) it snowed, the
children didn't go to school
 If (When/Whenever) it rained, the streets
were wet. = The streets were wet if
(when/whenever) it rained.

6.  !! NEVER WILL FUTURE in if- clause !!
 If + Present Simple !!! will + bare
infinitive
 If the weather is fine next weekend, we
will go for a walk.
 If it rains tomorrow, the streets will be wet
(tomorrow). = The streets will be wet if it
rains tomorrow.

7.  Verb (to) be = WERE ('was' can also be
used, but is less usual)
 If + Past Simple would + bare infinitive
 If I were you, I wouldn't do it. – If the
weather were fine, we would go
out.(=but it isn't fine)
 If it rained, the streets would be wet. (but
it isn't raining)

8.  If + Past Perfect would + have + past
participle
 If I had known you were coming to
Malaga, I would have met you at the
airport.
 If it had rained yesterday, the streets
would have been wet. (but it didn't rain)