趋向：trend, tend

下斜坡：declivity

下斜坡的：declivous

倾斜：incline, lean, bend, bias, dip, slant

倾倒：topple and fall, topple over

倾塌：collapse

倾覆：overturn, topple, tumble, capsize

端正：straight, upright

平坦：even, smooth, level, flat

平稳：steady, smooth and steady, stable

平衡：balance, equilibrium