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【单选题】
纳米二氧化钛(TiO 2 )可净化室内空气,TiO 2 中Ti的化合价为
A.
+2
B.
-4
C.
+4
D.
-2
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【单选题】某学校为新生开设了 4 门选修课程,规定每位新生至少要选其中 3 门,则一位新生不同的选课方案共有()
A.
4 种
B.
5 种
C.
6 种
D.
7 种
【单选题】I had to buy of these books because I didn’t know which one was the best.
A.
both
B.
none
C.
neither
D.
all
【单选题】I didn’t know the girl you the sheep.
A.
had fed
B.
had her fed
C.
had feed
D.
had to feed
【单选题】某学校为新生开设了4门选修课程,规定每位新生至少要选其中3门,则一位新生不同的选课方案共()。
A.
7种
B.
4种
C.
5种
D.
6种
【简答题】I didn’t know I had opened Pandora’s box when I entered this room.
【单选题】I sooner but I didn’t know that they were waiting for me.
A.
had come
B.
was coming
C.
would come
D.
would have come
【单选题】某学校为新生开设了4门选修课程,规定每位新生至少要选其中3门,则一位新生不同的选课方案共有 ( )
A.
7种
B.
4种
C.
5种
D.
6种
【简答题】某学校要对学生成绩进行计算机管理。该学校有若干学生,每个学生有学号、班级、姓名、性别、出生日期、地址。开设的课程需要管理课程编号、课程名称、学分和学生选修该课程后的成绩等信息。该学校规定:一个学生可以有选修多门课程,一门课程可以有多名学生选修。 1. 画出此管理系统的ER模型。 2. 简述ER模型向关系模式转换的一般方法。 3. 将以上ER模型转化为关系模式,包括主键、外键。 4. 试用S...
【单选题】我国关于葡萄酒的保质期一般会写( )年。
A.
5~8
B.
8~10
C.
10~12
D.
12~15
【简答题】When I was a kid I didn’t know what I wanted to be when I grew up, but I knew what I didn’t want to do. I didn’t even really know what one was. My elder brother is deaf. Growing up, I ended up defendi...
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