低氧对呼吸的刺激作用是通过______
行为调节、内分泌调节、遗传调节和食物调节都属于种群自动调节机制。
教育起源于儿童对成人的无意识模仿。
某日，甲翻越马路隔离带横穿马路，恰逢乙骑自行车路过。乙因骑车时查看手机，未能及时发现甲，致甲被自行车撞倒受伤。甲要求乙赔偿，乙拒绝。甲遂诉至法院。 问：
美国东部的气候顶极是夏绿阔叶林，但因常受火烧而长期保留在松林阶段，这属于______
下列关于阴道的叙述，正确的是______
正常人在安静、清醒、闭目状态时，所记录的脑电图主要是______
举例说明教师在教学中如何帮助学生掌握科学概念。
Mary said her mother (would buy her) a (five-speeds) racing bicycle (for) his (sixteenth birthday).
当f(0)=______时，f(x)=ln(1+kx)在x=0处连续．
(Two-thirds) of (the) area (are) covered by (water).
After all, ______ her faults are, she is Arnold's mother.
下列被继承人的亲属中，属于第二顺序法定继承人的是______
孙某婚后因海啸事故下落不明3年，其父母可以申请法院______
Pick out the appropriate expressions from the eight choices below and complete the following dialogue by blackening the corresponding letter on the Answer Sheet. A. It's time to go shopping. B. There's no way. C. About what? D. I have an interview next Monday. E. Which bank? F. How do I get there? G. The director seems to like me. H. Chances are slim!
诉讼时效作为权利人不行使权利就丧失请求人民法院保护其民事权利的法定期间，它一般只适用于______