20.The librarian did some careful checking and found several books__ from the shelf.
A、leaking
B、missing
C、losing
D、dropping
I . Phonetics( 5 points)Directions:In each of the following groups of words, there are four underlined letters or letter combinations marked A, B, C and D. Compare the underlined parts and identify the one that is different from the others in pronunciation. Mark your answer by blackening the corresponding letter on the Answer Sheet.1.( )