See to it that all the light (are) turned off before you lea

1 在句型 see to it that 句子 裏面,see to it that 句子（谓语动词是一般现在时）.所以,你的句子裏面用的是are turned off,而不是 should be turned off,也不是 must be turned off.
相同的结构还有：make sure that + 句子（谓语动词是一般现在时）.
John,make sure that your work IS finished before next Friday,will you