试题题干
Word Formation
Complete the following sentence with the proper form of the word in the bracket.
(act) They took 
steps to prevent the spread of the disease.
参考答案
试题解析
此处缺少形容词。
took是谓语，steps是名词。形容词修饰名词。所以变act为形容词active，“-ive”形容词后缀。
句意：他们采取了积极的措施来阻止疾病的传播。