http://www.wizards.com/default.asp?x=mtgcom/daily/mr261
黑神怒下面第二段
We』re also giving them out in packs a little differently than we did in Time Spiral. In Time Spiral, each pack had one rare, three uncommons, ten commons and a 「purple rarity」 timeshifted card. In Planar Chaos, you get the following in each booster: one rare, two uncommons, eight commons,
one uncommon or rare timeshifted card, and three common timeshifted cards. Yes, this means that you get four timeshifted cards per pack. And yes, you can still get two rares (and unlike Time Spiral you can actually get two gold-symboled rare cards). The uncommon timeshifted cards, by the way, show up in a 3:1 ratio with the rare timeshifted cards. For those bad at math, this means that in four packs, you should (on average) get three uncommon and one rare timeshifted cards.