modalverb
高二英语modalverb
做而实际未做的事 .“本来可以 … ” (may/can have done没这意思 ) eg: He might / could have given you more help, even if he was very busy. should/ought to + have done, 肯定句中，表过去应该做而实际未做；否定句中，表过去不该做的事 却做了。 eg: 1) I