If [img=67x35]1803e23a529c456.png[/img]exists and [img=67x35]1803e23a5bdddbb.png[/img] does not exist，then [img=134x35]1803e23a638f5a2.png[/img] must not exist.
举一反三
- True or False : If [img=52x32]1802ddd740eab2f.png[/img] does not exist and [img=51x32]1802ddd748fbd7e.png[/img] does not exist either, then [img=94x33]1802ddd750d8d30.png[/img] does not exist. A: True. B: False. C: - D: -
- 若[img=67x35]1802dbd0ad6fa0c.png[/img]存在，[img=67x35]1802dbd0b5f8a34.png[/img]不存在，则[img=134x35]1802dbd0be79aab.png[/img]一定不存在.
- 若[img=67x35]1802cdb7afe2fac.png[/img]存在，[img=67x35]1802cdb7b80fada.png[/img]不存在，则[img=134x35]1802cdb7c449ed0.png[/img]一定不存在.
- 若[img=67x35]18038487f9f1919.png[/img]存在，[img=67x35]180384880219f22.png[/img]不存在，则[img=134x35]1803848809fd232.png[/img]一定不存在.
- 若[img=67x35]1802cdc0c36f830.png[/img]存在，[img=67x35]1802cdc0cc8c612.png[/img]不存在，则[img=134x35]1802cdc0d476b97.png[/img]一定不存在.