Joe accidentally spilled his drink on Eric, Eric got up and insulted his mother, and before you know it, they were going at it.

The choice of a Riemannian manifold - roughly speaking, a differentiable manifold whose every point has a tangent space with a defined metric - means it is possible to define a differential form over it.

Lady Frederick: Oh lord, I wish I were eighteen. [She sinks into a chair, and an expression of utter weariness comes over her face.] Gerald: I say, what's up? Lady Frederick: [Starting.] I thought you'd gone. Nothing.

They breed like tribbles, but at least they’re not terrestrial.