When was the play going to begin?可以改.?

When was the play going to begin.这句可以改成 When did the play going to begin吗``一直搞不懂疑问句...
还有,Of courese you can,为什么不能用 could和might)

When the wolf was at the door when the businessman was leaving for home I was playing the piano when I was reading nespaper. when i was boy,the most exciting thing was when to celebrate the Spring Festival. When was the last time you saw the parrot? When the little girl saw the snake,she was ____ the food，（）good，was soon sold out when it was taken to the market It was midnight when the patient was rushed to the nearest hospital. he was walking in the forest when he was bitten on the leg by a sanke When was the Shenzhen Special Economic Zone founded?