（explain） 　Jack didn't give a very adequate ________ for being l

（explain） 　Jack didn't give a very adequate ________ for being late.
【正确答案】：explanation
【题目解析】：构词知识题。空格处前面是动词give和形容词adequate，显然空格处要填一个名词。explain是动词，变为名词需要去掉in再添加名词后缀-nation。因此正确答案是explanation，表示“解释；说明”。