Derek Shepherd (Patrick Dempsey) constantly desires more than Meredith (Ellen Pompeo) is willing to give. How long until he reaches his breaking point.
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You can't deny that the younger Grey sister is a cutie ... even if you don't approve of her flirtations with other characters! Lexie Grey has made an impression on viewers in Season 4.
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These two don't seem to interact much, but we love Drs. Alex Karev and Meredith Grey. One of the few pairings not to have hooked up on Grey's Anatomy!
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Alex Karev (Justin Chambers) without the familiar arrogant look. How will he handle the fallout from hooking up with Lexie Grey?
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Grey's Anatomy Season 4 Episode 7 Quotes

Meredith: [narrating] Before we were doctors, we were med students, which meant we spend a lot of time of studying chemistry. Organic chemistry, biochemistry, we learned it all. But when you're talking about human chemistry only one thing matters: either you've got it or you don't.

Derek: What's new with you?
Meredith: I saw my half-sister half naked.