PRESENT TENSES
They __________ (not/know) the answer to that question, so they __________ (wait) for the teacher to explain.
don’t know / are waiting
I ___ (walk) home last night when I suddenly ___ (realize) I had left my passport in the taxi.
was walking / realized
Past continuous sets the background action (walking). Past simple interrupts with a sudden realization.
By this time next year, I ___ (complete) my PhD and will be looking for a postdoctoral position.
will have completed
Future perfect: completion before a specific future point.
She ___ (not realize) she ___ (lose) her passport until she reached the airport.
didn’t realize / had lost
She only discovered (past simple) something that had already happened (past perfect).
By the time she handed in her thesis, she ___ (write) for nearly three years.
had been writing
Duration process over time (3 years).
As part of the interview process, candidates __________ (have) to solve a series of complex problems that __________ (require) careful thought.
have / require
She ___ (practice) the violin for two hours when the neighbors finally ___ (complain).
had been practicing / complained
Past perfect continuous emphasizes the duration leading up to the complaint. Past simple marks the neighbors’ action.
Look at those clouds! It ___ (rain) any minute now.
is going to rain
Going to: prediction based on present evidence (the clouds).
After he ___ (finish) the manuscript, he immediately ___ (send) it to the publisher.
had finished / sent
Past perfect shows completion before the later past action (sending).
They finally closed the deal after they ___ (negotiate) for months.
had been negotiating
Ongoing process leading to the deal.
I __________ (not/like) how things __________ (turn) out recently. Everything __________ (seem) to be going wrong.
don’t like / is turning / seems
We ___ (not see) each other since we ___ (graduate) from university.
haven’t seen / graduated
Present perfect (“haven’t seen”) shows the situation continues until now. Past simple (“graduated”) pinpoints a finished event in the past.
This time tomorrow, they ___ (interview) the final candidate.
will be interviewing
Future continuous: action in progress at a specific time tomorrow.
They ___ (evacuate) the building by the time the firefighters ___ (arrive).
had evacuated / arrived
Evacuation completed (past perfect) before firefighters showed up (past simple).
When the police questioned him, he ___ (drive) for over ten hours straight.
had been driving
Continuous, ongoing activity explains fatigue.
The manager __________ (not/like) when employees __________ (arrive) late, but today he __________ (work) from home, so no one __________ (know) if he will notice.
doesn’t like / arrive / is working / knows
I ___ (work) on the project all morning when the system suddenly ___ (crash).
had been working / crashed
Past perfect continuous highlights ongoing activity before a sudden past interruption (past simple).
At 9 o’clock tonight, I ___ (attend) the gala dinner, so I won’t be available by phone.
will be attending
Future continuous: event in progress at that time.
Hardly ___ (she/finish) her speech when the audience ___ (burst) into applause.
had she finished / burst
Past perfect with inversion (“Hardly had…”) → marks immediate succession.
The director was furious because the actors ___ (arrive) late repeatedly.
had been arriving
Repeated, continuous habit up to that point.
They __________ (plan) to launch the new product next month, but they __________ (not/announce) the exact date yet.
are planning / haven’t announced
I ___ (not hear) from him for weeks, and then out of the blue, he ___ (call) me last night.
hadn’t heard / called
Past perfect to mark the long silence before the call; past simple for the sudden call last night.
According to the timetable, the train ___ (depart) at 6:15 sharp.
departs
Present simple: timetable/schedule.
No sooner ___ (we/sit) down than the lights ___ (go) out.
had we sat / went
Past perfect with “No sooner…” → emphasizes one event instantly following another.
No sooner is a formal expression used to emphasize that one event happened immediately after another.
It’s normally followed by an inversion (auxiliary + subject), just like in questions.
Structure
No sooner + had + subject + past participle + than + past simple
Meaning
➡ As soon as one thing happened, another thing followed right after.
She was nervous because she ___ (wait) for the interview for more than an hour.
had been waiting
Continuous duration explains nervousness.