I’m afraid that…句式中的that从句是什么从句

有朋友在本站“答疑中心”问：I’m afraid that…句式中的that从句是什么从句。

关于“形容词+that从句”中that从句充当什么成分，查了一下有关语法著作。各家观点如下：

■《张道真英语语法》认为：“be+形容词”这类结构后常可跟从句，在概念上有时接近宾语，但在结构上接近状语：

I’m afraid (=fear) I have made a serious mistake. 我担心我犯了严重错误。

We are sure (=know for sure) that we shall succeed. 我们有把握会成功。

We are confident (=believe) we can overcome these difficulties. 我们有信心克服这些困难。

I’m not sure (=don’t know for sure) where she lives. 我不敢肯定她住哪里。

I’m not sure whether he still works there. 我不能肯定他是否还在那里工作。

I’m not certain who he is. 我不能肯定他是谁。

She was not certain whether he would come. 她不能肯定他是否会来。

■章振邦的《新编英语语法》认为：语法学家们对此看法不一。

有人认为that从句是状语从句。如：

I’m glad you like it.

= I’m glad because you like it.

也有人认为是同位语从句。如：

I’m amazed that you should have arrived so early.

= I’m amazed at the fact that you should have arrived so early.

也有人认为是宾语从句。如：

I’m afraid thatg she can’t succeed in her plans.

=I fear that she can’t succeed in her plans. (www.yygrammar.com)

■《牛津英语语法》认为：这类是名词性从句，但没说明是宾语从句还是同位语从句。