Exercício: Gap filling exercise

Pessoal,

Do meu homework:

(5) _______ now, few species had been removed from the register and when they (6) _____, it was usually because (7) _______ had finally become extinct.

- o 'register' é a lista de animais em extinção
- a dificuldade tá no 6, mas por favor chequem os demais.

Eu respondi:
(5): Until - apesar de achar que 'until now' não concorda com "had been removed"
(6): were? had? be?
(7): they