【正确答案】正确答案：In group(1), the second parts of the three sentences all cancel the implied meaning of the first part by adding some extra contents. This is a character of cancellation of conversational implica-ture. The presence of a conversational implicature relies on a number of factors; the conventional meaning of words used, the CP, the linguistic and situational context, etc. , if any of them changes , the implicature will also change. This can be done simply by adding more information, like the examples in group(1). When the second parts are added, the original implicatures are no longer there. In group(2), the case is very different because the two parts of those sentences are self-contradictory. While in group(1), even the second part"s function of cancellation of implicature is based on the truth-value of the first part. So each second part in group(1)" s sentences will not change the truth-value of its corresponding first part. But in group(2), the sentences" second part actually deny the truth value of the first part, thus the two parts are inconsistent with each other and can not exist simultaneously. The sentences examples in group(2)are considered self-contradictory and then not acceptable.