so as not to

他非常安静地走进去，以免吵醒婴儿。

He went in very quietly ___so ___as ___not ___to wake the baby.

我们带了一个备用轮胎，以免爆胎时被困住。

We brought a spare tyre ___so ___as ___not ___to be stranded if we got a puncture.

宇航员把自己固定住，以免睡觉时四处漂浮。

Astronauts fasten themselves down ___so ___as ___not ___to float around while they sleep.