1) What does Nestle believe?
2) Which products does the company still produce today? (я так поняла, тут в "produced" опечатка, прошедшее время+still, да ещё и today может быть только в пассиве, а тут актив). Тогда можно второй вариант вопроса в пассиве: Which products are still produced by the company today?
3) How much did a sponsor agree to invest in the idea?
4) Why did Sabber tell Jack to hang up?
5) Who is/are (в вопросе лучше is, хотя учительнице не понравится) coming to show me a new program that I want to buy?
6) When were we working so that we could ski all day?