以下之connectives對不對?

1. correct: Take a bath before you go to bed.
2. correct: Nick has been ill since his father came home.
3. the conjuction is correct but there is a prepositon missing in your sentence. In additon, classwork is uncountable.: Read it over before you hand IN your classwork.
4. Again, the conjuction 'before' is correctly used but there is some grammatical mistakes in your sentence: Danny did not leave the classroom before/until Miss Mak told him to.
5. We don't normally start a sentence with 'before'. Grandmother lets Mimi and Kitty play before they attend their lessons.
6. I'm not quite sure what you want to say in the subordinate clause. People normally use will instead of shall with children. I also think that you have used a wrong conjunction in this sentence.

The children will not get good seats unless they arrive early.

1 - correct
2 - Nick has been sick since his father came home.
3 - Read the classwork over before you hand it in.
4 - Danny did not leave this classroom until Miss Mak told him to do so.
5 - Grandmother let Mimi and Kitty play after they had attended their lessons.
6 - The children would not get good seats unless they came early.

Hope this will help you!!