乐队成员们认真地演奏着乐器，配合默契。

The orchestra members play their ___instruments attentively and in perfect harmony.

实验室里的精密仪器需要定期校准。

The precision ___instruments in the lab need regular calibration.

我们需要在公证处签署这些法律文件。

We need to sign these legal ___instruments at the notary office.

法律是维护社会正义的重要工具。

Laws are essential ___instruments for upholding social justice.