She was moving out of her old apartment she suddenly realized that the key to the new apa

问题补充：

She was moving out of her old apartment she suddenly realized that the key to the new apartment wasn’t on her.

A. until

B. once

C. when

D. as if

答案：

A. until

B. once

(答案→)C. when

D. as if

解析：连词辨析。 A.直到……B.一旦 C. 当……时 D.好似。句意：当她意识到她的新公寓的钥匙没有带在身上时，她正在走出她的旧公寓。选C。