In general, present tenses may be followed by a wide variety of tenses as long as the sequence fits the logic of the sentence.

The four present tenses are the simple present, the present progressive, the present perfect, and the present perfect progressive. When these tenses are used in an independent clause, the verb in the dependent clause can be a present tense verb, a past tense verb or a future tense verb, as in the following sentences.

Deborah waits patiently while Bridget books the tickets.

The simple present tense is used in both the independent clause and the dependent clause.

They have not delivered the documents we need.

The verb of the independent clause "They have not delivered the documents" is in the present perfect tense. The verb in the dependent clause "we need" is in the simple present tense. The simple future could also be used in the dependent clause ("we will need").

I have been relying on my Christmas bonus to pay for the gifts I buy for my large family.

In this sentence the compound verb of the independent clause ("I have been relying on my Christmas bonus to pay for the gift") is in the present perfect progressive. The simple predicate of the dependent clause ("I buy for my large family") is in the simple present ("buy"). The simple future could also be used ("will buy").

Even though the coroner has been carefully examining the corpse discovered in Sutherland's Gully since early this morning, we still do not know the cause of death.

In this sentence the compound verb of the independent clause ("we still do not know the cause of death") is in the simple present tense. The simple predicate of the dependent clause ("Even though the coroner has been carefully examining the corpse discovered in Sutherland's Gully since early this morning") in the present perfect progressive tense ("has been . . . examining").

The government has cut university budgets; consequently, the dean has increased the size of most classes.

In this compound sentence, both predicates are in the present perfect. The simple future could also be used in the second independent clause ("consequently, the dean will increase the size of most classes") if the writer wants to suggest that the dean's action will take place in the future.