刻板言语是指（）

A．联想过程缺乏一定方向，概念间缺乏内在联系

B．大脑中反复出现的观念，明知不必要，却摆脱不了，感到非常痛苦

C．以往经验在记忆中大量脱失

D．持续地重复某一单调的语句

E．缺乏事实依据，患者却坚信不疑的病理信念

_____earth scientists understand how and why earthquakes happen, forecasts are usually inaccurate.

A．As

B．While

C．Because

D．If