她用铁链把大门锁上了。

She used a metal ___chain to lock the gate.

这家连锁超市在全国有超过200家分店。

This supermarket ___chain has more than 200 stores across the country.

一个简单的错误引发了一连串的麻烦。

A small mistake triggered a ___chain of troubles.

他们用锁链把自行车拴在栏杆上。

They ___chained the bicycle to the railing.