【题目】She was about to tell me the secret ________ someone patted her on the shoulder.
A.as
B.until
C.while
D.when

【答案】D
【解析】句意：她正要告诉我这个秘密，这时有人拍了一下她的肩膀。be about to do...when...是固定句型，意为“正要做……这时……”。所以答案是D.