Future perfect

Form-->Subject + will + have + past participle

1. Future perfect is often used with by (by the time..., by next year, by tomorrow, etc.).
a. By the time we finish remodeling our house, we will have spent over twenty thousand dollars.
b. Henry began working at the company when he was twenty two years old. By the time he is fifty, he will have worked there for twenty-eight years.

Future Perfect Progressive

Form-->Subject + will + have + been + verb-ing

1. The future perfect progressive has basically the same meaning as the future perfect when used with the verbs work and live.
a. Henry began working at the company when he was twenty two years old. By the time he is fifty, Henry will have been working at that company for twenty eight years. Henry will have worked at that company ... would have the same meaning.

b. Paula came to San Antonio in March of 2002. By March of 2007, she will have been living or will have lived in San Antonio for five years.

2. In some cases the future perfect progressive and the future perfect have different meanings.
a. Correct-->By the time we have our vacation in July, we will have saved enough money to go to Puerto Vallarta.
b. Incorrect--> By the time we have our vacation in July, we will have been saving enough money to go to Puerto Vallarta.

Using Been
Been is the past participle of be.
We arrived at the bus stop at 4:00. It is now 4:50. In ten minutes we will have been here for an hour.

Negatives and Questions
1. Negative: We won't have saved enough money to buy a new car.
2. Yes/No Question: Will you have already gone to bed by the time I get home?
3. Information Question: How long will we have been driving when we get to Kansas City?