Complete the following sentence with a (compound) word derived from the one(s) given in bracket.
The professor gave a very （ ） lecture on the market economy yesterday．(inform)
【正确答案】：INFORMATIVE
【题目解析】：
根据前文a very和后文lecture名词可知空格处应该填形容词形式，inform的形容词为informative使人增进知识的。句意：这位教授昨天作了一次关于市场经济的内容丰富的讲座。