音乐会在开始前，安保团队已就位。

The security team ___was ___in ___position before the concert started.

请确保所有设备为实验就位。

Please ensure that all equipment ___is ___in ___position for the experiment.

象棋棋子已全部就位，准备开始游戏。

The chess pieces ___are ___in ___position for the game.