[update] commentaries about the last class

In the last class the  teacher introduced for her students the topic called  "relative clauses of time" that is a short information inside the phrase. For instance in the sentence" Thanksgiving is a day when North Americans celebrate the harvest, we have "a day when..." like the relative clause because it brings a new information about the sentence.
She  also talked about the adverbial clauses , that indicates time. These adverbs can be termed as Adverb Clause of Time.
These clauses begin with conjunctions such as whenever,while, after, before, since, when, as, as soon as,  till, etc…
• When you have finished your work, you may go home.
In this sentence, the clause ‘when you have finished your work’ indicated the time when you may go home.
• I will do it when I think fit.
In this sentence, the clause ‘when I think fit’ is indicating the time for me to do the work.