請用中文詳細寫出各句子運用了什麼 tense。
e.g: Three days ago,a fire broke out in the factory.(過去式)
1.The children were playing basketball when it started to rain.
2.By early next month,the new book have been published.
3.Maggie has been waiting for the result since last week.
4.No one seems to know where the servant has gone.