The Rules of the Sequence of Tenses
The choice of the tense form in the subordinate clause depends on the tense form
used in the principle part. This dependent use of tenses in certain types of clauses is
known as the rules of sequence of tenses.
In certain types of subordinate clauses the tenses are
used relatively (относительно), i.e. the tense form shows whether the action of the
subordinate clause is simultaneous (одновременно) with the action of the principle
part, precedes (предшествует) it or follows it.
1) The verb in the principle part is in one of the present or future tenses --- we use
the tense required by the situation in the subordinate clause.
e.g. They wonder (will wonder) where Sam is (was, has been, will be).
2) The verb in the principle part is in one of the past tenses --- there is a shift of
tenses (сдвиг времен) into the past.
a) The action of the subordinate clause is simultaneous with the action of the
principle part - the Past Simple or the Past Continuous is used.
e.g. Nobody knew what he meant. I thought you were joking.
b) The action of the subordinate clause precedes the action of the principle part the Past Perfect or the Past Perfect Continuous is used in the subordinate clause.
e.g. Everybody knew where she had been, what she had been doing.
c) The action of the subordinate clause follows the action of the principle part - the
Future-in-the-Past (Simple or Progressive) is used.
e.g. I was afraid that she would talk too much. She knew that George would
be waiting for her.
Note: these rules are compulsory (обязательные) when the action of the subordinate
clause is viewed from the past. But they are optional (факультативные, то есть могут
соблюдаться, а могут и нет) in present-time contexts. This is found in dialogues,
newspapers, radio reports.
e.g. Mary said she has been ringing you all day, Mother. I told Lewis that we
are worried about her.
These rules are not observed (не соблюдаются) in some cases:
a) the speaker believes that he is talking about things which are true all the times
(a universal truth)
e.g. He made me understand what love really is. The teacher said the river
flows into the Baltic Sea.
b) with the modal verbs must, should, ought to
e.g. He said she should be more careful.
c) the Past Continuous remains unchanged.
e.g. He said, "When I saw them they were playing tennis". He said that
when he saw them they were playing tennis.
d) the Past Simple is not normally changed into the Past Perfect in subordinate
clauses of time beginning with when and since.
e.g. He said, "When we lived in Paris we often saw Paul". He said that
when they lived in Paris they often saw/had seen Paul.
e) there is a concrete past date
e.g. He said he was born in 1995.