问题
选择题
I usually walk _________ home at 6:00 in the evening.[ ]
A. to
B. at
C. the
D. /
答案
答案：D
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I usually walk _________ home at 6:00 in the evening.[ ]
A. to
B. at
C. the
D. /
答案：D
考虑定义在事务集(T1，T2，T3) 上的调度S1和S2，S1与S2是否是冲突等价的为什么
| S1 | S2 | ||||
| T1 | T2 | T3 | T1 | T2 | T3 |
| read(P) | read(Q) | ||||
| read(Q) | read(P) | ||||
| write(Q) | write(Q) | ||||
| write(Q) | write(Q) | ||||
| write(P) | write(P) | ||||
| write(P) | write(Q) | ||||
| write(P) | write(P) | ||||
| read(P) | read(P) | ||||