1 We know how long he has been working

2 I remember how long she has been teaching English

3 you know how long they have been playing hockey

4 she remembers how long you have been waiting for it

5 he knows how long we have been building that house

6 they remember how long I have been traveling

7 I like how long she has been doing her homework

8 he understands how long his friend has been cooking

9 you see I have just received this email.

10 he has already done his homework

11 this is the worst film I have ever seen

12 that is the most beautiful place you have ever visited

13 it's the most expensive food she has ever eaten