在相同条件下,H2和CO的混合气体aL,完全燃烧时消耗相同条件下的O2bL.则a与b的关系正确的是( )
A.a=b
B.a=2b
C.a=0.5b
D.a=3b
答案:B
Not until they left school ____how much their teachers loved them and helped them.
A.that they realized
B.had they realized
C.when they would realize
D.did they realize
(31)到(35)题使用下列数据表。 “学生”表:学号C(8),姓名C(8),性别C(2),系名(10),出生日期D “课程”表:课程编号C(4),课程名称C(12),开课系名C(10) “成绩”表:学号C(8),课程编号C(4),成绩I
向“成绩”表末尾插入一条“学号”为“08102002”,“课程编号”为“4001”,“成绩”为“86”的新记录,正确的命令是( )。
A.INSERT INTO 成绩 VALUES(08102002,4001,86)
B.INSERT INTO 成绩 VALUES (" 08102002","4001",86)
C.INSERT FOR 成绩 VALUES(08102002,4001,"86")
D.INSERT FOR 成绩 VALUES("08102002","4001",86)