Hello Marc Bart, Broadly speaking, you can use "could" everywhere you can use "was/were able to", but you can't use "was/were able to" everywhere you can use "could". This is because "be able to" only refers to ability (in the strictest sense, not including know-how: "I am physically capable of swimming in cold water" = "I am able to/can swim in cold water", but, "I know how to swim" = "I can swim"), whereas "can/could" refers to ability among other things. In other words, the meaning of "could" is wider than the meaning of "was/were able to". To answer your question, then, "I could come" could (conditional :) ) be either conditional or past; the context should make it clear because when "could" is being used as a conditional, you are likely to find words referring to the present, and when it is being used as a past tense, you are likely to find words referring to the past - for example, "I could (=conditional) come but I don't want the neighbours to see me leaving the house," or "I could (=past) come and go as I pleased when I still had my car." There are occasionally ambiguities due to the fact that real conditions in the past are formed "if + past simple + past simple", (for example, "If my mum sent me to the shops, I always bought some sweets for myself with the change.") and unreal conditions in the present are formed "if + 'past simple' + past modal" (for example, "If my mum sent me to the shops, I would be happy to help.") Therefore, it is possible to have sentences such as, "If I stayed with my aunt, I could stay up until midnight," which could mean, "In the past, whenever I stayed with my aunt, I was allowed to stay up until midnight," (=real condition in the past) or, "I am not staying with my aunt at the moment, but if I were, I would be allowed to stay up until midnight." (=unreal condition in the present) Hope this helps! Alvin

@ Erik I hate to quibble, but if it really is the case that "I could come" is only conditional, never past, how would you account for a sentence such as, "My parents were great: when I was a teenager, I could come home late without them telling me off," or indeed for the use of "could" required by the sequence of tenses in noun clauses in sentences such as, "As there was no reply when I knocked the door, I thought that I could come in"? All the best, Alvin

In response to your second question: .....what's the difference between "I could come" and "I was able to come"? When using could or able to in reference to ability in the past ,there are two cases: 1) Speaking in GENERAL about past ability ( includes the negative using COULDN'T) 2) Speaking about one SPECIFIC completed action. GENERAL past ability--- and COULDN'T I could come home whenever I wanted then. I couldn't come home again. I could speak French when I was a young boy. I couldn't speak French when I was a young boy. The American soldiers couldn't accomplish their mission. (More correct than, The American soldiers were not able to accomplish their mission....although both forms are used.) SPECIFIC past ability The American soldiers were able to accomplish their mission (NOT, The American soldiers could accomplish their mission) Of course English speakers don't always follow rules. Language is a living thing! Grammar always lags behind actual usage. Денис

Marc, In response to your first question. ...when you say "I could come" is it conditional or past? Alvin is correct: it is a matter of context. Erik is correct: "I could come" by itself is ambiguous. My thinking on the question: COULD when it means, "be able to" is the past of modal CAN. -I could come here whenever I wanted when I was young and strong. -I could speak French when I was young. COULD is also an auxiliary verb. (formed from the past of CAN) -I could come to see you, what do you think? (suggestion) Past: I could have come to see you, what do you think? -Could I come? (polite request) -I could come to the party ( less than 50% possibility) Past: I could have come to the party. - I couldn’t possibly come. (impossibility negative only) Past: I couldn’t possibly have come. - If you need me, I could come. (in all types of conditional sentences) Past: I could have come if you had needed me. (etc.) "be able to" is fairly simple. We use it sometimes instead of can and could with the meaning "to have the ability to" Present: I am able to come Past: I was able to come (and other past tenses) Future: I will be able to come. (and other future tenses) "Can” meaning "being able to", has "could" for its past tense form. Present: I can come. I can speak Spanish. Past: I could come (then, but not now). I could speak Spanish then but not now. Future: no distinct future form Can has several meanings in the present tense: ability, permission, request,etc. Денис

Puede utilizar 'could come' como conditional o past. Las traducciones serian: 'Podría venir' - "If I had my car, I could come to the party." 'Podría venir' - "Could you come, please?" 'Podía venir' - "I could come when I had my car, but now I can't anymore." 'Pude venir' - "Since I had my car, I could come to the party friday." Con 'could have come', serian: 'Podría haber venido' - "If you had invited to the party, I could have come." Y con 'was able to' serian: 'Pude venir' - "I was able to come." 'He podido' - "I was able to come until now."