梳棉生条中，纤维以（）形态为主。
A.前弯钩
B.后弯钩
C.伸直状态
D.两端弯钩
参考答案：B
对于学生信息表：student(sno，sname，sex，age，dept)，能够得到年龄在20岁于22岁之间的学生的姓名和学号的语句是
A．SELECT * FROM student WHERE age BETWEEN 20 AND 22
B．SELECT sname，sno FROM student WHERE age BETWEEN 20 AND 22
C．SELECT sname，sno FROM student WHERE age＞＝20
D．SELECT sname，sno FROM student WHERE age＜＝22
