__you__(discover)who had been sending you the flowers these

英语动词时态问题：Did you ever discover who sent you the flowers.你搞清楚 Here -----（be）the card and these flowers for you patients who had been given the new drug were as Have you ever received or sent flowers?Who were these flower __you__ on the playground when you were at middle school? Who后面的动词如何判断用不用第三人称单数形式?如 Do you know who (discover)the pen? The flowers were so lovely that they_ in no time.填had been s It must have been they who picked the flowers.这里的强调句的must ha "what have you been eating these days?"the doctor asked. who was the_______ of america,do you know?(discover) 改错：1.all these years they had been contributing money to the You ( ) watering the flowers.