第067句：发展缓慢

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.

译文：

行为科学之所以发展缓慢，一方面是因为用来解释行为的依据似乎往往是由直接观察而来的，另一方面是因为一直很难找到其他解释。

点睛：

该句的主干是The behavioral sciences have been slow to change...，表语形容词后的动词不定式to change可以叫做宾语。两个because引导的原因状语从句由and连接，构成并列结构。

考点归纳：

动词不定式可以跟在充当表语的形容词之后，这样的不定式可以叫做宾语，具体如下：

*在表情绪的形容词之后
I'm eager to see my friends.
我急于见到我的朋友。

*在表状态的形容词之后
She is determined to go back to work.
她决心回去上班。

*在表品质的形容词之后
You are brave to act like that.
你那样做很勇敢。