Плизз помогите нужно правильно указать степень!

1) Heart disease is the largest cause of death in the world. (large) 2) The day of Tragedy is one of the most sad days for our people. (sadly) 3) This box is too large for the toys.Give me smaller one please. (large,small) 4) He was a successful journalist. (successful) 5) during the vacation I attended some interesting lectures. (interesting)