sidle|sidled|sidles|sidling

猫悄无声息地侧身向鸟靠近。

The cat ___sidled toward the bird without making a sound.

他悄悄地侧身挪到门边，不想被人发现。

He ___sidles up to the door, trying not to be seen.

那个害羞的男孩悄悄溜进教室，尽量不引起注意。

The shy boy was ___sidling into the classroom, trying not to draw attention.