Grammar: ⚙️ Verbs in Depth: ⏳ Perfect Continuous & Future Perfect Tenses (B2) - Lesson 7: Future Perfect Continuous (Duration of an action up to a certain future time)

⚙️ Lesson 7: Future Perfect Continuous

Welcome to one of the most advanced English tenses! After learning about actions that will be *completed* by a future time (Future Perfect Simple), we now learn how to talk about the *duration* of an action leading up to that future time. We use the Future Perfect Continuous¹ to answer the question: "By that time, for how long will this action have been happening?"

The Structure: will have been + -ing

Although it seems long, the structure is very regular and combines elements you already know. It describes an ongoing action that will continue up to a specific point in the future.

Formula: Subject + will have been + Verb-ing

• Positive: "By the time you arrive, I will have been waiting for an hour."
• Negative: "He won't have been feeling well for long when he decides to see a doctor."
• Question: "Will you have been living here for ten years by the next election?"

Focus on Duration at a Future Point

The main purpose of this tense is to measure the duration² of an activity from its start to a specific future point. We almost always use it with a time reference like "by..." or "by the time..." and a duration phrase like "for...".

"By the end of this year, I will have been working at this company for five years."

"When he finishes his course, he will have been studying graphic design for three years."

Future Perfect Simple vs. Continuous

The difference is the same as with other perfect tenses: focus on completion vs. duration.

Simple (Focus on completion³):
"By the time I'm 30, I hope I will have visited ten countries." (Focuses on the number, the result).

Continuous (Focus on duration):
"By the time I'm 30, I will have been travelling for several years." (Focuses on the long, ongoing activity of travelling).

Remember Stative Verbs!
As always, we cannot use continuous tenses with stative verbs⁴ (like know, be, own). Use the Future Perfect Simple for these.
Correct: "Next year, we will have been married for a decade."
Incorrect: "Next year, we will have been marrying..."

🧠 Practice Quiz: Choose the Correct Tense

Complete the sentences with the correct Future Perfect Simple or Continuous form.

1. By the time the bus arrives, we _______ (wait) for nearly two hours.
   Answer: will have been waiting (Focus is on the duration 'for two hours'.)
2. By 2030, scientists _______ (discover) cures for many more diseases.
   Answer: will have discovered (Focus is on the completed achievement/result.)
3. In September, she _______ (teach) at that school for twenty years.
   Answer: will have been teaching (Focus is on the duration 'for twenty years'.)
4. When you finish your plate, you _______ (eat) three whole bowls of noodles!
   Answer: will have eaten (Focus is on the completed number 'three bowls'.)
5. Next year, I _______ (live) in Battambang for a decade.
   Answer: will have been living (Emphasizes the continuous duration. 'will have lived' is also possible but less focused on the ongoing nature.)

📝 Homework: Look Forward in Time

Answer these questions about your future using the Future Perfect Continuous.

1. How long will you have been studying English by the end of this year?
   (Example: By the end of this year, I will have been studying English for five years.)
   _________________________________________
2. Think about a hobby you have (like playing guitar, reading, or a sport). In two years' time, how long will you have been doing it?
   (Example: In two years' time, I will have been playing guitar for seven years.)
   _________________________________________
3. Complete this sentence: "When I retire, I _______ (work) for over 40 years."
   Answer: will have been working

Vocabulary Glossary

1. Future Perfect Continuous: (Noun Phrase) - អនាគតកាលបរិបូណ៌កំពុងបន្ត (â'néa'kât'tâ'kal bo'rĭ'bao kâmpŭng bântɔɔ) - A tense describing the duration of an action up to a specific point in the future. ↩
2. Duration: (Noun) - រយៈពេល (rô'yĕă' peil) - The length of time that something continues. ↩
3. Completion: (Noun) - ការបញ្ចប់ (kaa bânh'châp) - The action or state of being finished. ↩
4. Stative Verb: (Noun Phrase) - កិរិយាស័ព្ទប្រាប់សភាព (kĕ'rĭ'ya'sâp prăp sa'phéap) - A verb describing a state of being rather than an action (e.g., know, love, believe, own). ↩
5. Look forward: (Phrasal Verb) - ទន្ទឹងរង់ចាំ (tŭn'tœ̆ng rông'chăm) - To feel pleased and excited about something that is going to happen. ↩