Sally is a student of Grade Eight． She always works hard (11 ) her lessons． English is her favorite (12 )． She thinks that it is as (13 ) as Chinese， but it's more difficult (14 ) than Chinese． For example， a lot of English words and expressions are hard to remember．She often carries her walkman with her， and she spends time (15 ) English tapes every day．It (16 )her listening better and better．

Sally is (17 ) student in her class． She often helps her classmates (18 ) their lessons after (19 ) her homework． Most of her classmates like t0 (20 ) her when they have ques- tions． They think she is smart and outgoing．( )11．

A．in

B．at

C．for

D．of

[单选题]24．________ in Grade Eight now．A． John and his sister are bothB． John isC． John's sister isD． Michael is

[试题]根据下列材料请回答 51～60 题：In Grade Eight I took physics．In one test I get 51．____________only 36 percent of the answer correct．I failed the 52．____________next one，either．I started to think that maybe l was 53．____________not good at it．However，1 was not luck

[单选题]关系模式Student(Sno，Sname，Cno，Cname，Grade，Tname，Taddr)的属性分别表示学号，学生姓名，课程号，课程名，成绩，任课教师名和教师地址。其中一个学生可以选若干门课，一个教师可以讲授若干门课，一门课程可以由多个教师讲授，对于同一门课程，学生只能选定一个教师讲授一门课，教师不会重名。下列对关系的分解正确的并且是无损连接及保持函数依赖的是______。A．{(Sno，Sname，Cno，Tname，Taddr)，(Sno，Sname，Cno，Cname，Grade

[主观题]建立“student”和“grade”两表之间的关系。

[单选题]关系模式Student(sno，Sname，Cno，Cname，Grade，Tname，Taddr)的属性分别表示学号、学生姓名、课程号、课程名、成绩、任课教师名和教师地址。其中，一个学生可以选若干门课程，一个教师可以讲授若干门课程，一门课程可以由多个教师讲授，对于同一门课程，学生只能选定一个教师讲授的课程，教师不会重名。下列有关关系模式Student的分解中，是无损联接并保持函数依赖的是——。A．{(Sno，Sname，Cno，rname，raddr)，(sno，Sname，Cno，Cnarn

[单选题]对于学生信息表：student(sno，sname，sex，age，grade)，查询学习成绩为空的学生的学号和姓名，下面语句正确的是A．SELECT sno，sname FROM student WHERE grade=NULLB．SELECT sno，sname FROM student WHERE grade IS NULLC．SELECT sno，age FROM student WHERE grade IS NULLD．SELECT sno，age FROM student WHERE

[单选题]已知关系:STUDENT(sno,sname,grade),以下关于命令“CREATE CLUSTER INDEX s_indexON student(grade)”的描述中,正确的是A．按成绩降序创建了一个聚簇索引B．按成绩升序创建了一个聚簇索引C．按成绩降序创建了一个非聚簇索引D．按成绩升序创建了一个非聚簇索引

[单选题]已知关系：STUDENT(sno，sname，grade)，以下关于命令“CREATE CLUSTER INDEX s_index ON student(grade)”的描述中，正确的是A．按成绩降序创建了一个聚簇索引B．按成绩升序创建了一个聚簇索引C．按成绩降序创建了一个非聚簇索引D．按成绩升序创建了一个非聚簇索引

[单选题]已知关系：STUDENT(sno，sname，grade)，以下关于命令 “CREATE CLUSTER INDEX s_index ON student (grade)” 的描述中，正确的是( )。A．按成绩降序创建了一个聚簇索引B．按成绩升序创建了一个聚簇索引C．π按成绩降序创建了一个非聚簇索引D．按成绩升序创建了一个非聚簇索引

[单选题]对于数据表：student(sno,sname,sex,age,grade)，查询学习成绩为空的学生的学号和姓名，下面语句正确的是______。A．SELECT sno,sname FROM student WHERE gade=NULLB．SELECT sno,sname FROM student WHERE grade IS NULLC．SELECT sno,age FROM student WHERE grade IS NULLD．SELECT mo,age FROM student WH