题目内容
A man does not know the difficulty of anything _____ he does it personally .
| A.although | B.if | C.because | D.unless |
D
连词unless本身具有否定意义:if … not,引导的是否定的条件句,这种否定的条件句从反面来表达强烈的语气,一些语法学家称它为"反面的唯一条件句"又如:One cannot master a foreign language well unless he studies it hard . (不下苦功夫,是学不好的一门外国语的。)
练习册系列答案
相关题目