20.In October 2007,the Chang'e-l satellite was successfully __at Xichang.
A、launched
B、presented
C、regulated
D、engaged
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 answer by blackening the corresponding letter on the Answer Sheet.