7、sunanswered.B.Readthequestionscarefullybeforeansweringthem.C.Guesstheanswerifyoucannotanswerthequestion.二、单项选择(15分)()21.Does the man need_______ operation at once, Doctor Li? A.aB. anC. theD. /()22.Whichoftheunderlinedpartsisdifferentinpronunciation?A.litter B.pi