I couldn't tell if his refusal to talk was simple stubbornness.是什么意思？

I couldn't tell if his refusal to talk was simple stubbornness.

我不清楚他拒绝说话是否只是因为他的顽固不化。

tell

vt. 告诉，说，辨别，吩咐，讲述；vt.& vi. 分辨，辨别，告诉，吩咐，泄漏，保证；vi. 泄密，告发，（颜色、声音等）显示，识别；n. [考古学]（古代村落遗址堆积而成的）台形土墩，[方言]讲的话，谈话，传闻；

例句
'You can tell that he is extremely embarrassed,' Mr Brigden added...
“你能看出他尴尬极了，”布里格登先生补充道。

if

conj. 如果，倘若，即使，〈口〉是否，假设；n. 条件，设想；

例句
She was old enough to absent herself from the lunch table if she chose...
她长大了，可以自己做主不来吃午餐了。

his

pron. (he的所有格)他的，(he的物主代词)他的东西；det. 属于他的，用于名词前，自己的，指某人的，上帝的；

例句
He claimed that his parents had abandoned him...
他声称父母遗弃了他。

refusal

n. 拒绝，优先取舍权；

例句
They cited Alex's refusal to return to the marital home...
他们引证了亚历克斯拒绝回到婚后的家中一事。

to

prep. 向，朝着，到，关于，属于；adv. 朝一个方向的，到某种状态，关闭；

例句
I suggest you leave it to an expert...
我建议你把它留给专家来解决。

talk

v. 说话，讨论，讲，说，说闲话；n. 交谈，讨论，报告，空话；

例句
...trying to talk above the noise...
努力使说话声高过噪音

was

v. 用来表示某人或某物即主语本身，用来表示某人或某物属于某一群体或有某种性质（ be的过去式 ），在，存在，不受干扰；

例句
There was a terrible sadness in her eyes...
她眼神中流露出深深的悲伤。

simple

adj. 简单的，单纯的，易受骗的，天真的；n. 笨蛋，愚蠢的行为，出身低微者；

例句
The older child should be able to prepare a simple meal...
那个年纪稍大的孩子应当会做一顿简单的饭菜。

stubbornness

n. 倔强，顽强，牛性，牛脾气，犟劲；

例句
Matt looked at Hugh and saw the stubbornness in the set of his shoulders...
马特看着休，从他坚挺的肩膀中看出了他的倔强。