really know who built Stonehenge," says Paul Stoker. "And perhaps we might never know, but we do know they must have been hardworking ---- and great planners!"

要点详解

1.Why do you think the man is running?

本句由"疑问词+do you think+其他"构成的特殊疑问句。在此结构中，如果特殊疑问词在句中作主语，特殊疑问句语序不需要变化；如果特殊疑问词在句中不作主语，特殊疑问句用陈述句语序。

Who do you think is the tallest in your class?

Where do you think we should go for a holiday?

2.He could be running for exercise.

could be running 情态动词+be+doing 结构，表示推测正在进行或发生的动作

I think he could be watching TV at home.

3. No, he is wearing a suit.

suit 此处用作可数名词，意为"西服；套装"Today my teacher wears a suit.

suit可作动词，适合，适宜 suit sb fine 很适合某人 suitable adj 适合的

短语 be suitable for

I think blue clothes suit her very fine.

The story is not suitable for young children.

4.He might be running to catch a bus to work.

catch 赶上 词组 catch up with 赶上某人

catch 的一词多义： catch the ball catch the bus catch the chief catch a cold

5.expressing a difference 表达不同之处

express v 表达，表示（思想和感情） express...to sb. 对某人表达 。。。