They failed to pass the exam last time,I regretted___.A.being unable to help B.not to be able to help请解释为什么.regret to do 和 regret doing 的区别

Susan failed to pass the exam,( 反义疑问句 He failed to pass the test反问怎么问? He failed to pass the axam,(我也） they who should come failed to appear. They failed to pass the exam last time,i regretted_____A、to be not able to helpB、being unable to helpC、being not able to helpingD、not be able to help选哪个 为什么? They failed to pass the exam last time,I regretted___.A.being unable to help B.not to be able to help请解释为什么.regret to do 和 regret doing 的区别 be not able to do sth be unable to do sth区别They failed to pass the exam last time,I regretted ___.A.being unable to helpB.being not able to help They tired to climb the high mountain,h____,they failed. failed to pass在反义疑问句中为什么用否定He failed to pass the exam 改否定句为什么用didnt he求 I failed to pass...表示过去,为什么不能是I fail to passed? fail an exam的近义词是啥?是Failed to pass the exam吗? he failed ----- the final exam A.to pass B passing请说明原因 Though he worked hard,he failed to pass the ____ exam.(enter) 单句改错 He searched for all his pockets but failed to find his pass. They failed to come yesterday.改为同义句? They had failed to locate the ship they had been sent to look for.翻译. They have ____(success)to pass the exam 关于单词regret的用法```They failed to pass the exam last time.I regretted ____ them.A to be not able to helpB being not able to helpC not being ablt to helpD not be able to help(我看不出BC有什么区别,希望高手给出正确答案和