I saw him enter the room, unlock a drawer, take out a document, photograph it and put it back.
我看见他进了房间，打开抽屉的锁，取出文件，照了相，然后又把它放回去。
She fail to unlock the safe in spite of all her exertion.
她虽然费尽力气，仍未能将那保险箱的锁打开。
Scientists have unlocked the secret of the atom.
科学家已经揭开了原子的秘密。
