Complete the sentences with the past perfect of the verb in brackets:
1.Kevin (go)...................home by the time I arrived.
2.Ethan suddenly realized that he (leave)...................his laptop on th train.
3.Mum was annoyed because I (not clean)...............my room.
4......................they (study).................English before they went to the USA ?
5.We were hungry because we (not eat)...........................
6.My phone didn't work because I (not charge)....................it
7.Why didn't you want to watch the film? -................you (see)...................it before?
8.Sally was embarrassed because she (forget)..................her dad's birthday.
9.I (never/see)...................such a beautiful beach before I went to Kauai.
10.I did not have any money because I (lose)...............my wallet.
11.Tony knew Istanbul so well because he (visit).............the city several times.
12.We were not able to get a hotel room because we (book)............in advance.