English Grammar

Tenses

#TenseAspectOccurenceUsageExamples
1.PresentSimplecommonRoutine, fact, habit, schedule. Actions taking place one after another.I eat pizza everyday. She writes books.
2.Continuouscommon(Temporary) action in progress at the moment. Replacement of future "going to" + time marker (arrangements).I am eating pizza now. She is currently writing a book. She is writing a book tonight.
3.PerfectuncommonAction started in the past and stopped recently (until now) influences present - no time specified. Result is important. OR [1]I have eaten all of the pizza. She has already writen 40 books. She has been a writer for 15 years.
4.Perf. Cont.uncommonAction started in the past and is still going on - time specification needed. Duration is important. Impossible with state verbs.I have been eating pizza for two hours. She has been writing books since she was 18.
5.PastSimplecommonAction completed at a specified time in the past. Actions taking place one after another. Action taking place in the middle of another action.I ate pizza yesterday. She wrote that book many years ago.
6.ContinuousuncommonAction in progress in the past was interrupted by 2nd action or specific time marker. Actions taking place at the same time.I was eating pizza when you arrived. She was writing that book when she become ill.
7.PerfectrareAction completed in the past before 2nd action or specific time marker. The fact is important. I had eaten all of the pizza when you arrived. She had writen that book before she became ill.
8.Perf. Cont.rareAction started in the past, continued for some time, then is interrupted by 2nd action or time marker. The duration is important.I had been eating pizza for two hours when you arrived. She had been writing that book for a few months when she became ill.
9.FutureSimplecommonDecision at the time of speaking. Plans or possibilities which are not sure. Assumptions about distant future.I will eat pizza tomorrow. She will probably write a book this afternoon.
10.ContinuousuncommonAction not completed in the future interrupted by 2nd action or time marker. Replacement of "going to" - future plan or arrangement.I will be eating pizza when you arrive. She will be writing a book tomorrow at 6 pm.
11.Perfectvery rareAction completed before another action or time marker in the future. "by" or "in" is necessary.I will have eaten all of the pizza by the time you arrive. She will have finished writing that book by midnight.
12.Perf. Cont.very rareAction that continues for some time in the future is interrupted by 2nd action or time marker. Duration is important.I will have been eating pizza for two hours when you arrive. She will have been writing a book for few hours by that time.
13.Future "going to"commonActions planned for the future, or certain to happen in the near future. Decision or plan already made.I am going to eat pizza. She is going to write a book.
14.Future in PastrareActions planned in the past, that possibly didn't happen.I was going to eat pizza. (but didn't) She was going to write a book.

[1] State verbs (no start and finish): agree, appear, be, believe, belong, concern, consist, contain, depend, deserve, disagree, dislike, doubt, feel (=have opinion), fit, hate, have (=own), hear, imagine, impress, include, involve, know, like, love, matter, mean, measure, mind, need, owe, own, prefer, promise, realize, recognize, remember, see (=understand), seem, suppose, suprise, taste (=smell), think (=believe), understand, want, weigh, wish. State verbs don't take continuous aspects!: use simple or perfect aspect instead.

Conditionals

#TensesUsageExamples
0If + Present Simple → Present SimpleFact. "When" instead of "if" possible.If you heat ice, it melts. It is easier to relax, if you close your eyes.
1If + Present Simple → Future SimpleHigh probability.If I see her tomorrow, I will speak to her. I will not let them in if they are late again.
2If + Past Simple → wouldLow probability or hypothesis.If I saw her tomorrow, I would speak to her. If I were a lawyer, I wouldn't take on this case.
3If + Past Perfect → would havePast situation, zero probability.If I had seen her yesterday, I would have spoken to her.