Modal VerbModal VerbCan (could) , may ( might), must (must), have to (have got to), shall (should), will (would), need (need) , ought to , dare ( dared)1
can, could , be able toMan cannot live without air
I’ll not be able to come this afternoon
I can’t come this afternoon 以下情况只能用 be able to
不能用 could
He was able to swim half-way before he was wore out
( 经过一番努力才完成的事) He was able to go to the party yesterday evening客观主观( can) ( 主观,而且“某件事已成功” ) This cannot be done by him
How can you be so careless
How (who )can tell…
惊异,怀疑,不相信(否定,疑问,感叹句)Could I come to see you tomorrow
( 表语气) Yes ,you can
/ No, I’m afraid not
表推测,猜测
S+can/ could+ not +v Can/ Could+ s+ vCan this news be true
( 对现在状态的推测)The man can’t be our new teacher
S+ can/ could +not be +v-ing Can/could+s+be+vingHe can be reading in th