Спросите, почему это так. they take big bags.-why do they take big bags? she takes sandwiches.-why does she take sanwiches? 1.they go home. ? 2.they take the flags. ? 3.they like the cheese. cheese? 4.he likes the game. game? 5.she likes the film. film? 6.the dog plays with the toy. the toy?

В данном случае, чтобы задать вопрос, нужно поставить вопросительное слово why на первое место, дальше вс глагол (does в 3л., ед.ч, do в остальных случаях), подлежащее и глагол в первой форме без каких-либо окончаний.
1.They go home.
Why do they go home?
2.They take the flags.
Why do they take the flags?
3.They like the cheese.
Why do they like the cheese?
4.He likes the game.
Why does he like the game?
5.She likes the film.
Why does she like the film?
6.The dog plays with the toy.
Why does the dog play with the toy?