Student: Professor Lance, your lecture on cloning is very interesting! Professor: ______ Are you a student of biology Student: No. I major in chemistry. A: I think so B: I"m glad to hear that C: It must be D: It"s not so interesting

W: Can we leave the lab now, teacherM. No, you must tidy the lab before you leave. When can the student leave(). A: The student can’t leave unless he has put everything back in the cupboard. B: The student can leave after he turns off the electricity. C: The student can leave after he has tidied the lab.

【多选题】针对学生选课数据库S_T，以下()操作实现了student表与sc之间的自然连接。 A. select student.* ,  cno,  grade  from student  join   sc  on  student.sno=sc.sno B. select student.* ,  sc.*  from student ,  sc  where student.sno=sc.sno C. select student.sno, sname, ssex, sage, sdept , cno, grade  from student ,  sc  where student.sno=sc.sno D. select student.* , cno, grade  from student ,  sc  where  student.sno=sc.sno

Number the events in the order they happen. A: The male student stands up and leaves the table. B: The male student thanks the female student. C: They introduce themselves to each other. D: Two students are studying in the library. E: They shake hands with each other. F: The female student picks up the wallet and runs after the male student.

Speaker A: () Speaker B: I’m a student. Speaker A: What are you studying Speaker B: Medicine. A: Are you a student B: What are you doing C: How do you do D: What do you do