第三人稱單數後的can用不用加s
不用加s,因為can是情態動詞,它不隨人稱的變化而變化,無論是第幾人稱,或單數或複數,can都不變。
例如 I can go to school
We can go to school 
She can go to school
They can go to school
但是 can 有時態的變化
它的過去式是could,過去否定形式是couldn't.
不用加s,因為can是情態動詞,它不隨人稱的變化而變化,無論是第幾人稱,或單數或複數,can都不變。
例如 I can go to school
We can go to school 
She can go to school
They can go to school
但是 can 有時態的變化
它的過去式是could,過去否定形式是couldn't.