At last he ___finishi the work ahead of time.A.couldB.was able to C.could have done D.would have been able to请问一下B.D的区别、would have been 的意思是什么、?be able to do 与can do 的区别是什么?wouldn't/won't的用法是什么

HE ____(STAY) AT HOME LAST NIGHT He decided for __________ at last At last he received their ____(invite) . At last he ( ) (意识到) he made a big mistake. he is good at math last year同义句转换 He _____(练习) English at home last night. He did his homework last night.用 at night 改写 He at the camp last week.[be动词填空】快 At last he walked _____the forest and saw the village He helped this little boy ______ his father at last At last he lost his temper同意句钻换 At last he heard what i _____(say ) At last he didn't say nothing about it.改错 at last he s() in swimming across the river at last,he 什么 in finishing the work at last he a_____ with me填单词 he was at the party last night改否定句 改为同义句：He passed the exam at last.