Although the various shades of time and sequence are usually conveyed adequately in informal speech and writing, especially by native speakers and writers, they can create havoc in academic writing and they sometimes are troublesome among students for whom English is a second language. This difficulty is especially evident in complex sentences when there is a difference between the time expressed in an independent clause and the time expressed in a dependent clause. Another difficulty arises with the use of infinitives and participles, modals which also convey a sense of time. We hope the tables below will provide the order necessary to help writers sort out tense sequences.

As long as the main clause's verb is in neither the past nor the past perfect tense, the verb of the subordinate clause can be in any tense that conveys meaning accurately. When the main clause verb is in the past or past perfect, however, the verb in the subordinate clause must be in the past or past perfect. The exception to this rule is when the subordinate clause expresses what is commonly known as a general truth:

• In the 1950s, English teachers still believed that a background in Latin is essential for an understanding of English.
• Columbus somehow knew that the world is round.
• Slaveowners widely understood that literacy among oppressed people is a dangerous thing.

The tables below demonstrate the correct relationship of tenses between clauses where time is of the essence (i.e., within sentences used to convey ideas about actions or conditions that take place over time).

Tense in Independent Clause	Purpose of Dependent Clause/ Tense in Dependent Clause	Example(s)
Simple Present	To show same-time action, use the present tense	I am eager to go to the concert because I love the Wallflowers.
	To show earlier action, use past tense	I know that I made the right choice.
	To show a period of time extending from some point in the past to the present, use the present perfect tense.	They believe that they have elected the right candidate.
	To show action to come, use the future tense.	The President says that he will veto the bill.
Simple Past	To show another completed past action, use the past tense.	I wanted to go home because I missed my parents.
	To show an earlier action, use the past perfect tense.	She knew she had made the right choice.
	To state a general truth, use the present tense.	The Deists believed that the universe is like a giant clock.
Present Perfect or Past Perfect	For any purpose, use the past tense.	She has grown a foot since she turned nine. The crowd had turned nasty before the sheriff returned.
Future	To show action happening at the same time, use the present tense.	I will be so happy if they fix my car today.
	To show an earlier action, use the past tense.	You will surely pass this exam if you studied hard.
	To show future action earlier than the action of the independent clause, use the present perfect tense.	The college will probably close its doors next summer if enrollments have not increased.
Future Perfect	For any purpose, use the present tense or present perfect tense.	Most students will have taken sixty credits by the time they graduate. Most students will have taken sixty credits by the time they have graduated.

Sequence of Tenses
With Infinitives and Participles

Like verbs, infinitives and participles are capable of conveying the idea of action in time; therefore, it is important that we observe the appropriate tense sequence when using these modals.

INFINITIVES
Tense of Infinitive	Role of Infinitive	Example(s)
Present Infinitive (to see)	To show same-time action or action later than the verb	Coach Espinoza is eager to try out her new drills. [The eagerness is now; the trying out will happen later.]
		She would have liked to see more veterans returning. [The present infinitive to see is in the same time as the past would have liked.]
Perfect Infinitive (to have seen)	To show action earlier than the verb	The fans would like to have seen some improvement this year. ["Would like" describes a present condition; "to have seen" describes something prior to that time.]
		They consider the team to have been coached very well. [The perfect infinitive to have been coached indicates a time prior to the verb consider.]
PARTICIPLES
Tense of Participle	Role of Participle	Example(s)
Present Participle (seeing)	To show action occurring at the same time as that of the verb	Working on the fundamentals, the team slowly began to improve. [The action expressed by began happened in the past, at the same time the working happened.]
Past Participle or Present Perfect Participle	To show action occurring earlier than that of the verb	Prepared by last year's experience, the coach knows not to expect too much. [The action expressed by knows is in the present; prepared expresses a time prior to that time.]
		Having experimented with several game plans, the coaching staff devised a master strategy. [The present perfect participle having experimented indicates a time prior to the past tense verb, devised.]