问题补充：
Our friends were busy with each other the time.
A. so; talking; that they forgot
B. too; talking; to forget
C. too; to talk; to forget
D. so; to talk; that they forgot
答案：
(答案→)A. so; talking; that they forgot
B. too; talking; to forget
C. too; to talk; to forget
D. so; to talk; that they forgot
解析：本题考查too…to；so…that…和be busy的用法。be busy doing sth忙于做某事。
句意：我们的朋友忙于交谈，以致忘了时间。so…that…如此……以致于……。
