Directions:In each of the following groups of words,there are four underlined letters or let-ter combinations marked A,B,C and D.Compare the underlined parts and iden-tdtify the one that is different from the others in pronunciation.Mark your answerby blackening the corresponding letter on the Answer Sheet
A、actress
B、business
C、excess
D、endless
19.The university regulations require that the students__ at least 90% of the lectures.