例句與造句

1. In algebraic geometry, the trefoil can also be obtained as the intersection in "'C "'2 of the unit 3-sphere " S " 3 with the complex plane curve of zeroes of the complex polynomial " z " 2 + " w " 3 ( a cuspidal cubic ).
2. It's difficult to find cuspidal cubic in a sentence. 用cuspidal cubic造句挺難的