When eleven o' clock came and he still hadn't arrived, I began to wonder if he had had an accident. 这句话为什么是对的?
I really miss the time___we spent together in middle school.这句话中的空格为什么不能填“when”?
The accident was happened when I was trying to find a place to park.这句话错在哪里?
My brother has joined the Youth League for years.这句话哪里错了?
详细地回答可以加分!