*The Future Perfect Tense:
-It is formed with (will have+p.p)
EX:They will have finished.
*The future perfect expresses an action that will be finished at a specific time or before that time in the future.
EX:I will have finished the exam before twelve o'clock.
EX:By the end of the week, I will have finished building the house.
EX:My father will have bought a car in a week.
EX:Before July,I will have travelled to England.
*The Future Perfect Continuous:
-It is formed with will+have been+v+ing.
EX:I will have been studying.
*The future perfect continuous is used to emphasize the continuous nature of an action.It is used in the same way and with the same expressions as the future perfect.
EX:By tonight, I will have been working for eleven hours without a break.(Future Perfect continuous)
EX:By tonight,I will have worked for eleven hours without a break. (Future Perfect)
Note:Not all verbs can be used in a continuous tense because of the meaning of the verb.Only verbs that show continuous action can be used : study,work,travel,write,listen,watch,and so on.
EX:I will have been watching the match.(Correct)
EX:I will have been arriving at the airport.(Incorrect)