“It’s a secret. Promise no one else would know it”, he lowered his voice and whispered no one could overhear it.
A. in case
B. even if
C. so that
D. just as
网友回答
A. in case
B. even if
(答案→)C. so that
D. just as
解析：短语辨析。A. 万一；假使 B.即使；虽然 C.以便；所以 D. 正如。句意：这是一个秘密。保证没有其他人知道。他压低声音低声说，以便没有人能无意中听到。选C。