【送分题】the plane was late and detectives were waiting at the a

【送分题】the plane was late and detectives were waiting at the airport all morning.
l有两个现在进行时的特例把我搞糊涂了
1、新概念2第七课的
the plane was late and detectives （were waiting ）at the airport all morning
这句为什么用过去进行时呢?“等了整整一个上午”又不是正在等一个上午,所以应该用过去完成时啊?“已经等了整整一个上午”这样说着才顺嘛2、she is always