哦,看了答案明白了。我对F选项的判断被Mg干扰了。(I thought: because #1.Mg cannot be in continuously < freez point, and #2. no Mg found, Conclusion: never > freez point. I failed to distinguish the necessary condition and the sufficient condition)
F must be true: Premise 1. has moved (penetrate) Premise 2. moisture (means "T > freez point") is necessary for the movement Therefore, has been "T > freez point" Premise 3. in recent years, T NOT > freez point Therefore, "T > freez point" sometime in the past
C must be false: Premise 1. Mg due to bac Premise 2. bac NOT survive in the "continuously frozen" place of Ant Conclusion: No Mg in "continuously frozen" place of Ant
Choice C: notice the qualifier "continuously frozen location". from our above conclusion, we should conclude "No Mg". also the extreme words: "when increase to ... BEGIN" (indicates IMMEDIATE action) and "SIGNIFICANT amounts"
(D) is guilty of the unjustified extreme words ("most""extreme"), so it cannot be must-be-true. It may be true that Fe-only rock is mostly found in mildly cold environment, not in extremely cold environment.
看看答案吧选 D F 花了4'12'' -- by 会员 babybearmm (2012/6/30 5:19:57)
|