第 70 题 (多选题)： Examine this command SQL> ALTER TABLE ORDERS SHRINK SPACE COMPACT.Which two statements are true.

A. Queries and DML statements are allowed on ORDERs while the SHRINK is executing. B. Dependent indexes become UNUSABLE. C. The SHRINK operation causes rows to be moved to empty space starting toward the end of the ORDERs segment. D. The SHRINK operation causes rows to be moved to empty space starting from the beginning of the ORDERs segment. E. Only queries are allowed on ORDERs while the SHRINK is executing. F. The high-water mark(HWM)of ORDERs is adjusted 显示答案