摘要：时态:文中两次出现have been，属于 be 动词的现在完成时，译为:一直、持续

01

今日长难句

The behavioral sciences have been slow to change partly because the explanatory items often seem to be directly observed and partly because other kinds of explanations have been hard to find.

02

词汇解析

explanatory adj. 解释性的(常作定语)

item 项目;一则;一件东⻄

observe 观察

主干:主语behavioral sciences + 系have been + 表语slow to change

时态:文中两次出现have been，属于 be 动词的现在完成时，译为:一直、持续

修饰:原因状语从句partly because，解释主干

04

参考译文

The behavioral sciences have been slow to change

partly because the explanatory items often seem to be directly observed andpartly because other kinds of explanations have been hard to find.

行为科学一直发展缓慢

原因1️⃣解释性内容，似乎通常源于直接观察

原因2️⃣其他类型的解释方法，始终难寻。

来源：佳意教育