2 sentences for 森严 (sēn​yán — tight)

1. 由于防备森严，小偷始终没能得手。

   yóu​yú fáng​bèi sēn​yán, xiǎo​tōu shǐ​zhōng méi néng dé​shǒu.

   The thief never succeeded because of the heavy security.

   Source: Dong Chinese Dictionary

2. 由于有重要首脑出席，会场的戒备非常森严。

   yóu​yú yǒu zhòng​yào shǒu​nǎo chū​xí, huì​chǎng de jiè​bèi fēi​cháng sēn​yán.

   Due to the presence of important leaders, security at the venue is very tight.

   Source: Dong Chinese Dictionary