12. When I opened the door, I heard him ________.
(A) sang
(B) singing
(C) to sing
(D) was singing

答案：登入後查看
統計： A(5), B(292), C(1), D(53), E(0) #211966

詳解 (共 1 筆)

#1345171
感官動詞+ing 表強調動作
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