The Korean tenses
When something happens and how it is seen — finished, in progress, already done before: that is the question every tense answers. Here are all the topics about it, each with its own page and its own exercises.
All 8 topics on tense and time
1The past tense -았/었-One syllable between the stem and the ending makes any verb or adjective past: 가요 becomes 갔어요.1The future with -(으)ㄹ 거예요The verb is turned into a modifier before 거 (thing) and the copula: 갈 거예요, "I will go" or "I am going to go".2The ending -겠-: intention, guessOne syllable before the ending that turns a statement into a firm intention, a guess from what you see, or a polite set phrase.2The progressive -고 있다Stem plus -고 있어요 for an action under way: 먹고 있어요, "I am eating".3The resulting state -아/어 있다After a change of state — sitting down, opening, arriving — -아/어 있다 says that the result is still there: 앉아 있어요, "she is sitting".3The double past -았/었었-A second -었- says that a past state or event no longer holds: 갔었어요, "I went (and came back)".3In the middle of: -는 중이다A verb before the noun 중 (middle) says that something has started and is not yet finished: 회의하는 중이에요.2How long: 동안, 만에 and 지나다동안 for how long something lasts, 만에 for how long until it happens, 지나다 for time going by.
Practise the tenses
Exercises from every topic on tense and time, mixed together. That is exactly the hard part: almost anyone can build a form when it says next to it which one is meant.