admire 后通常不接that引导的宾语从句，如：
不能说：I admire that he is brave.
可改为：I admire his bravery.
若一定要接that从句作宾语，可考虑改为the fact that结构。如：
I admired the fact that he would talk to students outside the classroom or talk with them on the telephone. 我羡慕他经常在课外与学生聊天或通过电话与学生聊天。——摘自2004年高考英语试卷
另外，admire虽然不能后接that从句，但可接连接代词或连接副词词引导的从句。如：
I admire how well she speaks English. 我羡慕她英语讲得那么好。
顺便说一句，admire后不接不定式的复合结构，即不说admire sb to do sth，要表示“羡慕(赞赏)某人做某事”，英语可用admire sb [sb’s] doing sth：They all admired his behaving so bravely. 他们钦佩他表现如此勇敢。