【单选题】正常情况下,维持呼吸中枢兴奋性的最有效刺激是
【单选题】正常情况下,维持呼吸中枢兴奋性的最有效刺激是
【简答题】______以“蜀山”为核心创作了30多部武侠小说,被称为中国现代武侠小说剑仙派代表作家。其代表作品为《 》。
【单选题】The ultimate purpose of the research is to ______.
A.
have a better understanding of the life of mosquitoes
B.
prevent human beings from being bitten by mosquitoes
C.
purify the environment