Listen.There must be someone_____ in the classroomA.sings B.to si_英语解答

Listen.There must be someone_____ in the classroom
A.sings B.to sings C.sing D.singing

人气：493 ℃　时间：2020-01-25 22:07:44

解答

Listen.There must be someone__D.singing___ in the classroom选D？？？是的，选D，前面listen已经说明是现在进行时