计算机是现代科学家必不可少的工具。

Computers are an essential ___tool for modern scientists.

根据我的个人经验，我也可以说个人电脑是一个非常棒的工具。

From my personal experience, I can also say that a personal computer is an amazing ___tool.

锤子是木工的基本工具。

A hammer is a basic ___tool for carpentry.