裸子植物通常可分为()、()、()、()和()等五纲。
参考答案:铁树纲;银杏纲;松柏纲(球果纲);红豆杉纲;买麻藤纲
根据下列各句句意和空白之后的汉语提示词或首字母,在答题卡指定区域的横线上写出对应单词的正确形式,每空只写一词。
小题1: Just be p________ for a while. These things take time.
小题2: When did you get ___________(订婚) ?
小题3: He was____________(好奇的) to know what was happening in the office.
小题4:The little girl is a _______(有天赋的) dancer.
小题5: The photo will r________ me of the days when we were together
小题6:They father bought some new f_____ last week, such as a sofa and a table.
小题7:I can’t remember__________(精确地) what she said.
小题8: J_______ from her letter, Mother seems to be feeling a lot better.
小题9: We should keep a balanced diet and exercise_________ (规律地)to keep fit.
小题10:The little girl hopes to meet a handsome prince, just like a princess in a fairy t__.
对于关系R,第二范式是要求R中的每一个非主属性满足
A.没有重复的组项
B.只有简单的重复项
C.完全函数依赖于主关键字
D.单值依赖关系