Что надо вставлять . 1 they were happy to get the invitation 2 yesterday your friends went to the cinema, 3 the group of students won't stay in the hotel, 4 his collection of stamps was the best, 5 the head teacher didn't write the letter,

1 They were happy to get the invitation letter,weren't they? 
2 Yesterday your friends went to the cinema, didn't they? 
3 The group of students won't stay in the hotel, will it? 
4 His collection of stamps was the best, wasn't it? 
5 The Head Teacher didn't write the letter, did he?