抛物线 $x^2=2y$ 的准线方程为（    ）

微生物群体生长的测定方法
①测定样品中的细胞数目                      ②测定次级代谢产物的总含量
③测定培养基中细菌的体积                    ④测定样品的细胞总质量

“盘旋在崇山峻岭之上/绵延峭拔的八达岭啊/舞起矫健的巨龙/短兵相接的年月/你是抵御外敌入侵的壁垒/和平建设的年代/你是显示民族气魄的支柱……”诗中赞美的我国古代的伟大工程是（     ）       

图为用DIS系统测得的小车做直线运动的s﹣t图，则小车在BD段做____运动，图中C点对应的运动状态的瞬时速度大小是____ m/s．

短文改错。
短文中共有10处语言错误，每行中最多两处错误。错误涉及一个单词的增加、删除或修改。
增加：在此处加一个漏字符号(∧)，并在其下面写出增加的词;
删除：把多余的词用斜线(＼)划掉;
修改：在错的词下划一横线，并在其下面写出修改后的词。
注意：1）.每处错误及其修改均仅限一词；
2）.只允许修改10处，多者(从十一处起)不计分。
    I am angry about the behavior of dishonest in exams. This doesn't mean I've never cheated. I once write the answers on my hand for a history test, but unluckily caught by my teacher. Because she was one of my most favorites, there were no words to describe what sorry I felt at that time. I thought cheat would help me keep my straight A. Little I know that I was hurting not only me but also my teacher. From this lesson I know our teachers want their students to succeed by learning with their own and do the best they can, not by cheating.