He was not altogether clear in his own mind about which type of political arrangement would be the most appropriate.他心里并不太明白哪种形式的政治安排是最合适的。

At that time it wasn't clear in my mind what had happened.那时我心里并不明白发生了什么。

I am quite clear in my mind that we need to change.我心里非常明白我们需要改变。