当李探长正试着摸电灯开关时，突然，房门被关上了，并从外面上了锁。
dāng Lǐ tànzhǎng zhèng shì zhe mō diàndēng kāiguān shí ，tūrán ，fángmén bèi guān shàng le ，bìng cóng wàimian shàng le suǒ 。
As Detective Li was feeling around trying to find the light switch, the door suddenly closed and locked from the outside.