Have you found out the c___of the accident?

Have you found out the c___of the accident? Have you found out the case anywhere?翻译 heve you ____the book you have been____?A.found ,looking for B.found out,looking forC.found,finding out D.found out ,finding You found out right You have found your lost umbrella,haven't you? Yes,I found it behind the door this morning.为什么答语中found不用have found? 英语词汇问题:found和found out的区别是什么?比如Have you found your lost book?中为什么只能用found? 英语词汇问题:found和found out的区别是什么?比如Have you found your lost book?中为什么只能用found?请具体说明一下, you have found your lost umbrella ,haven't you?yes,i_______it behind the door thisA have found B will find C found D find they have found out a great deal Have you found the best way to work out the problem同义句Have you found the best way_ _ _the problem Have you found the best way to work out the problem同义句Have you found the best way_ _ _the proble I have just found out that time really can change everything ,if not ,maybe you have never liked me Have you found your pen( have i found you是 where have you found it? where you have found contact if you hadn't foung me ,I would have found you. You must know that it is bad for your health though you haven't ____.A:found it B:found out it选哪个 为什么