非限制性定语从句的引导词不能用that吗?

非限制性定语从句不能用that引导.
1.非限制性定语从句 从句部分用逗号隔开,一般放在主语后面,修饰主语,或对其解释说明；去掉从句部分,往往意思不够明确,但对整个句子结构没有影响.
The house,which we bought last month,is very nice.
2.当先行词是专有名词或物主代词和指示代词所修饰时,其后的定语从句通常是非限制性的.
Charles Smith,who was my former teacher,retired last year.查理·史密斯去年退休了,他曾经是我的老师.
3.非限制性定语从句还能将整个主句作为先行词,对其进行修饰,这时从句谓语动词要用第三人称单数.
He seems not to have grasped what I meant,which greatly upsets me.他似乎没抓住我的意思,这使我心烦.