The document discusses the structure and use of second conditional sentences in English. It explains that second conditional sentences are used to talk about unreal or hypothetical situations in the present or future. The structure consists of an "if" clause using the past tense verb form followed by a main clause using "would" plus the base verb form. Examples are provided such as "If I had a million dollars, I would buy a big house" to illustrate talking about an unlikely present situation. The document also discusses using various time expressions like "when", "before", "after", "while" in adverb clauses and the tenses that should be used with each.

1. SECOND CONDITIONAL
The second conditional (also called conditional type 2) is a structure used
for talking about unreal situations in the present or in the future. This page
will explain how the second conditional is formed, and when to use it
THE STRUCTURE OF A SECOND CONDITIONAL SENTENCE
Like a first conditional, a second conditional sentence consists of two clauses,
an "if" clause and a main clause:
IF CLAUSE
MAIN CLAUSE
If I had a million dollars
I would buy a big house
If the "if" clause comes first, a comma is usually used. If the "if" clause
comes second, there is no need for a comma:
MAIN CLAUSE
IF CLAUSE
I would buy a big house
If I had a million dollars

2. We use different verb forms in each part of a second conditional
if clause
if + subject + simple past verb*
main clause
subject + would + verb
*Note that this "simple past" form is slightly different from usual in the
case of the verb BE. Whatever the subject, the verb form is "were", not
"was": If I were rich, I'd buy a big house.
Using the second conditional
The second conditional is used to talk about things which are unreal (not
true or not possible) in the present or the future -- things which don't or
won't happen:
Example
Explanation
If I were you, I would drive more carefully
in the rain.
I am not you -- this is unreal.
Paula would be sad if Jan left.
Jan will not leave -- that's not going to
happen.
If dogs had wings, they would be able to
fly.
Dogs don't have wings -- that's
impossible.

3. USING ADVERB CLAUSES WITH TIME EXPRESSIONS
These type of clauses are often called "time clauses" in
English grammar books and follow specific patterns.
Take a look at the chart below to study the various usage
of different time expressions.
Punctuation:
When an adverb clause begins the sentence use a
comma to separate the two clauses. Example: As soon
as he arrives, we will have some lunch.. When the
adverb clause finishes the sentence there is no need for
a comma. Example: He gave me a call when he arrived
in town.

4. ADVERB CLAUSES WITH TIME
WHEN
He was talking on the phone when I arrived.
'When' means 'at that moment, at that time,
etc.'. Notice the different tenses used in
When she called, he had already eaten
relationship to the clause beginning with
lunch.
when. It is important to remember that 'when'
I washed the dishes when my daughter fell takes either the simple past OR the present the dependent clause changes tense in
asleep.
relation to the 'when' clause.
We'll go to lunch when you come to visit.
BEFORE
We will finish before he arrives.
She (had) left before I telephoned.
AFTER
We will finish after he comes.
She ate after I (had) left.
'Before' means 'before that moment'. It is
important to remember that 'before' takes
either the simple past OR the present.
'After' means 'after that moment'. It is
important to remember that 'after' takes the
present for future events and the past OR
past perfect for past events.

5. WHILE, AS
She began cooking while I was 'While' and 'as' mean 'during that time'. 'While' and
finishing my homework.
'as' are both usually used with the past continuous
because the meaning of 'during that time' which
As I was finishing my homework, she
indicates an action in progress.
began cooking.
BY THE TIME
By the time he finished, I had cooked 'By the time' expresses the idea that one event has
dinner.
been completed before another. It is important to
notice the use of the past perfect for past events
We will have finished our homework
and future perfect for future events in the main
by the time they arrive.
clause. This is because of the idea of something
happening up to another point in time.
UNTIL, TILL
We waited until he finished his
homework.
I'll wait till you finish.
'Until' and 'till' express 'up to that time'. We use
either the simple present or simple past with 'until'
and 'till'. 'Till' is usually only used in spoken
English.
SINCE
I have played tennis since I was a
young boy.
'Since' means 'from that time'. We use the present
perfect (continuous) with 'since'. 'Since' can also
be used with a specific point in time.
AS SOON AS
He will let us know as soon as he
decides (or as soon as he has
decided).
'As soon as' means 'when something happens immediately afterwards'. 'As soon as' is very
similar to 'when' it emphasizes that the event will
occur immediately after the other. We usually use
the simple present for future events, although
present perfect can also be used.

6. WHENEVER, EVERY
TIME
Whenever he comes, we go to have lunch at
"Dick's".
We take a hike every time he visits.
THE FIRST,
SECOND, THIRD,
FOURTH ETC.,
NEXT, LAST TIME
'Whenever' and 'every time' mean 'each
time something happens'. We use the
simple present (or the simple past in the
past) because 'whenever' and 'every time'
express habitual action.
The first time I went to New York, I was intimidated The first, second, third, fourth etc., next,
by the city.
last time means 'that specific time'. We can
use these forms to be more specific about
I saw Jack the last time I went to San Francisco.
which time of a number of times something
happened.
The second time I played tennis, I began to have
fun.