MENGGUNAKAN COULD UNTUK MENGEKSPRESIKAN KEMUNGKINAN

(a)    A: Why isn’t Greg in class? B: I don’t know. He could be sick. (b)   Look at those dark clouds. It could start raining any minute.

Could can mean past ability   But that is not only meaning. Another meaning of could is possibility. In (a): “He could be sick” has the same meaning as “He may/might be sick,  i.e., “It is possible that he is sick.” In (a), could expresses a present possibility. In (b), could express a future possibility.