有一种通过寄生方式来繁衍后代的黄蜂，它能够在适合自己后代寄生的各种昆虫的大小不同的虫卵中，注入恰好数量的自己的卵。如果它在宿主的卵中注入的卵过多，它的幼虫就会在互相竞争中因为得不到足够的空间和营养而死亡；如果它在宿主的卵中注入的卵过少，宿主卵中的多余营养部分就会腐败，这又会导致它的幼虫的死亡。
如果上述断定是真的，则以下哪项有关断定也一定是真的
Ⅰ．上述黄蜂的寄生繁衍机制中，包括它准确区分宿主虫卵大小的能力。
Ⅱ．在虫卵较大的昆虫聚集区出现的上述黄蜂比在虫卵较小的昆虫聚集区多。
Ⅲ．黄蜂注入过多的虫卵比注入过少的虫卵更易引起寄生幼虫的死亡。
A．仅Ⅰ。
B．仅Ⅱ。
C．仅Ⅲ。
D．仅Ⅰ和Ⅱ。
E．Ⅰ、Ⅱ和Ⅲ。
参考答案：A
解析： 根据题干可以知道“上述黄蜂的寄生繁衍机制中，包括它准确区分宿主虫卵大小的能力”，即Ⅰ成立，如果Ⅰ不成立，就不可能“在适合自己后代寄生的各种昆虫的大小不同的虫卵中，注入恰好数量的自己的卵”；Ⅱ和Ⅲ很显然无法从题干中得到。
阅读下面短文，根据所读内容在表格中的空白处填入恰当的单词。 注意：每个空格只填一个单词。 Although stressful and unpleasant, examinations are a part of education that students all over the world have to experience. Exams are not recent methods of testing knowledge. They have been used since ancient times and our ancestors probably went through the same anxious preparation as students today. China, exams were first introduced more than 1,300 years ago during the Sui Dynasty. Known as the Imperial Examinations or keju, the ten subject tests were used to select people for government jobs. A career in public service was considered the highest profession, and the examinations attracted millions of hopeful participants each time they were held. The tests had three levels: for local, provincial and national government. Only about 5% of those taking each level passed, and the number of students who passed all the levels was even smaller－ perhaps as low as 0.0004%. The exams were so important in China that some people spent nearly their whole lives retaking the exams in the hope of eventually passing. Others tried to cheat by hiding notes in cakes or on their clothes. Historians found one undergarment that had 353 model essays written on it. Perhaps if this particular student had spent as much time studying as he did writing on his clothes, he would have passed! The Imperial Examinations lasted until 1905, when they were replaced. Exams, however, are still a compulsory part of education in China. As nobody has yet come up with an alternative method of judging students’ abilities, it seems likely that the system of examinations will continue for more years.
|