试题题干
Word Formations
Complete the following sentence with the proper form of the word in the bracket.
(significant) It is a waste of time to listen to his 
talk.
参考答案
试题解析
此处缺少形容词。
talk是名词，需要形容词修饰。根据前面的a waste of time可知，空格处填的应该是消极意义的词。所以变significant为其反义词insignificant。
句意：听他那些废话纯属浪费时间。