所有技术词汇都用红笔在下面画了线。

All the technical words have been ___underlined in red.

在屏幕上阅读时，标出重点会更困难。

It's harder to ___underline important points when you're reading on a screen.

他用红笔在课文的关键句子下面画线。

He uses a red pen to ___underline the key sentences in the text.