请教白勇语法p.97 No.25

25. In reference to the current hostility toward smoking, smokers frequently expressed anxiety that their prospects for being hired and promoted are being stunted by their habit.

(A) In reference to the current hostility toward smoking, smokers frequently expressed anxiety that

(B) Referring to the crrent hostility toward smoking, smokers frequently expressed anxiety about

(C) When referring to the current hostility toward smoking, smokers frequently expressed anxiety about

(D) With reference to the current hostility toward smoking, smokers frequently expressed anxiety about

(E) Referring to the current hostility toward smoking, smokers frequently express anxiety that

正确答案：E

后面的解释说：about是介词，只能加名词或-ing形式或名词性从句。

可是此题干中未划线部分是不是一个名词性从句呢？

如何分辨一个从句是名词性从句还是非名词性从句呢？请各位NN不吝赐教

anxiety that：后面接一个从句，表示对于这个anxiety的具体描述。未划线部分their prospects for being hired and promoted are being stunted by their habit.就是一个从句

anxiety about sth：接名词，表示对某东东的anxiety

谢谢而今迈步从头越说～～

不过未划线部分是不是一个名词性从句呢？

如何分辨一个从句是名词性从句还是非名词性从句呢？

这两个问题还是不大理解说，能否帮忙再解释一下么，不胜感激～～