Adverbial clauses

Purpose clauses
1. With “to” infinitive phrase.
I left the party early
to catch
the last bus.
or
I left the party early
in order to catch
the last bus.
or
I left the party early
so as to catch
the last bus.
For negative
She went downstairs barefoot
so as not to
2. With in order that, so, so that. (usually modals are used)
Refers to the present - can, may, will, shall
be heard.
in order not to
I have brought some coffee and a few sandwiches so that you
can
have a bite.
Refers to the past – could might should.
I
I packed swimsuits too so that we could have a swim.
in order that, so, so that
spoke slowly and clearly so that
the audience
could understand my explanations.
so as to
I walked out into the garden so as to weed the flowerbeds.

Reason clauses.
1. Talking about a possible situation explaining the reason why someone does something.
I am here just in case anything unusual
happens.
Present simple
I’ll stay here in case she arrives later.
2. In case expresses a precaution.
If refers to a result.
while
You insure things in case they are stolen. (before they are stolen)
You should telephone the police if your things are stolen. (you telephone after they have been stolen)

Time clauses.
I’ll tell him this funny story when he
comes.
Future tenses are not used
Every time
when
I meet Alex I remember our trip.
Каждый раз, когда я встречаю Алекса, я вспоминаю о нашей поездке.