A:accustomed to stay
B:accustomed to staying
C:used to stay
D:addicted to stay
(-1)18的绝对值是( )
已知四边形ABCD,有以下四个条件:①AB∥CD;②AB=CD;③BC∥AD;④BC=AD.从这四个条件中任选两个,能使四边形ABCD成为平行四边形的选法种数共有( )
下列说法不正确的是( )