问题补充:
nearly all behavior is learned behavior is a basic assumption of social scientists.
A. /
B. That
C. It is acceptable
D. When
答案:
A. /
(答案→)B. That
C. It is acceptable
D. When
解析:根据句子的结构分析,句中的nearly all behavior is learned behavior是一个完整的句子在充当主语,称为主语从句。that引导主语从句只起连接作用,没有实际含义,但不能省略。