同学你好，该知识点来自沪江网校《英语零基础直达大学六级【随到随学班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学好
本句中过去进行时were watching更强调在昨晚的7点到9点这个时刻一直在看足球赛。更强调在过去某一时刻或某一段时间内正在进行或持续进行的动作。而用had watched, 只是强调动作已经完成。

拓展：过去进行时与过去完成时的区别

一、过去进行时由助动词be 的过去式 ＋ 现在分词构成。其中be有人称和数的变化，第一、第三人称单数用was，其他用were.

1）过去进行时动词主要表示在过去某一时刻或某一段时间内正在进行或持续进行的动作。过去进行时经常与过去时配合使用。例如：

This time yesterday, we were having an English lesson.

昨天这个时候，我们正在上英语课。

The teacher was giving us a lesson when Tom walked into the room.

老师在给我们上课时，汤姆走进教室。

While we were having supper, all the lights went out.

我们吃饭的时候，灯灭了。

He was reading while she was setting the table.

她摆桌子时，他在读书。

It was getting dark. The wind was rising.

天渐渐黑下来了。风势增强了。

2）过去进行时动词常用always, continually, frequently 等词连用，表示过去经常发生的行为。这种用法表明带有的感情色彩。例如：

The two brothers were frequently quarreling when they were young.

两兄弟小时候常吵架。

In Qing Dynasty, China was always making concessions to western powers.

清朝时，中国总是对西方列强妥协。


二、过去完成时 一律用had + 过去分词构成。

1）表示发生在过去某一时间或动作之前的事情，即“过去的过去”。用过去完成时，必须有一个过去的时间或动作来作参照，说明在此之前某事已发生。如果两个动作都是在过去发生的，先发生的用过去完成时，后发生的用一般过去时。例如：

She told me she had been there three times before.

她告诉我她以前到过那里三次。（“去过”发生在“告诉”之前）

How long had he taught here by the end of last term?

到上学期末为止，他在这里教学多长时间啦？ （“教学”发生在上学期末结束之前）

When we arrived, the football match had already begun.

我们到的时候，足球赛已经开始了。

She had visited China twice before she came this year.

她今年来中国之前已访问过中国两次了。

2）过去完成时动词可以表示过去某一时刻之前发生的动作或呈现的状态，这一动作一直持续到过去这一时刻或将继续下去。例如：

By the middle of last month, I had lived in Beijing for five years.

到上月中旬，我已在北京住了五年了。

By six o’clock they had worked for eight hours.

到六点为止，他们已工作八小时了。

When I came to Shanghai, he had been there for a long time.

我到上海时，他在那里很长时间了。

3）过去完成时动词常用于间接引语和虚拟语气，我们以后会详细讲述。

4）此外，过去完成时常用于 no sooner…than… 和 hardly(scarcely) …when… 这两个句型，前面部分用过去完成时，后面部分用一般过去时。例如：

No sooner had he stolen the purse than he was caught red-handed.

= He had no sooner stolen the purse than he was caught red-handed.

他刚偷到钱包就被当场抓获。

Saddam had hardly realized what was happening when he was captured.

= Hardly had Saddam realized what was happening when he was captured.

萨达姆还没有意识到在发生什么事情就被抓获了。

希望能帮助到你，祝学习愉快！