I. CONDITIONALS
a. 1st Real present
If I find your watch, I will tell you.
b. 2nd Unreal present
If I found a watch in the street, I would take it to the police.
c. 3rd Unreal past
If I had known you were in hospital, I would have gone to visit you.
d. 1st + 3rd Real present + unreal past.
If Mark speaks English as perfectly as you say he does, he would have got a job in Brussels.
e. 2nd + 3rd Unreal present + unreal past
If she loved him, she wouldn't have left him.
f. 3rd + 2nd Unreal past + unreal present
If I had studied medicine when I was young, I would be a doctor now.
II. WISH/IF ONLY (If only is stronger)
I wish/ If only + sb/sth did (past simple) - to express wish or regret about the present or future
I wish I didn't work in a school.
I wish/If only + sb/sth had done (past perfect) - to express wish or regret about the past
He wishes he hadn't failed his exam.
I wish + sb/sth would do - to complain (only for actions; the subject must be different)
I wish it would stop raining.
III. IT'S (HIGH/ABOUT) TIME
IT'S (HIGH/ABOUT) TIME (FOR YOU) TO GO.
ITS' (HIGH/ABOUT TIME) YOU LEFT. - to emphasise your irritation; this action should have been already completed
III. Expressing Preference - WOULD RATHER, WOULD PREFER, PREFER, WOULD SOONER
1. the same subject
I'D RATHER (NOT) GO. (present)
I'D RATHER (NOT) HAVE GONE to the party last night. (past)
2. different subject
I'D RATHER YOU DIDN'T GO. (present)
I`D RATHER YOU HADN'T PHONED me at midnight. (past)
3. comparing
a) I'D RATHER WATCH A COMEDY THAN (WATCH) A THRILLER. =
I'D PREFER TO WALK HOME RATHER THAN TAKE THE BUS. (specific preference)
b) HE PREFERS (PLAYING) TENNIS TO (PLAYING) FOOTBALL. =
I PREFER TO EAT FISH RATHER THAN (EAT) MEAT. (general preference)
c) I'D SOONER DIE THAN MARRY YOU! - if you would sooner do something, you would much prefer to do it, especially instead of something that seems unpleasant
IV. Ggiving advice - SB HAD BETTER DO STH
You'd better see a lawyer. ~ You should/ought to see a lawyer. (less emphatic)
V. AS IF/AS THOUGH
Mary talks as if/as though she knew everything. (unreal present)
He had never been abroad, but he spoke as if/as though he had been there many times. (unreal past)