互联网已成为现代交流的强有力工具。

The Internet has become a very powerful ___instrument of modern communication.

这条机械狗在不启动时是无害的，但它是一种镇压和制造恐怖的工具。

This mechanical dog, harmless when not active, is an ___instrument of repression and terror.

他将教育视为社会进步的主要手段。

He viewed education as the primary ___instrument for social advancement.