She wrote the letter with blue ink.

她用蓝墨水写了那封信。

youdao

It took 40 injections of blue ink in order to complete this procedure.

这个过程总共注射了40次的蓝药水。

youdao

Her gaze dropped to the files stacked so neatly in front of her. She spotted a streak of blue ink staining the sleeve of her lab coat.

她盯着桌上堆放整齐的两叠文件，却一不小心余光扫到白大褂袖子上的一道蓝墨水。

youdao

The address was written in small letters in blue ink.

VOA: special.2009.12.26

First, though, the blocks are tested with red and then blue ink and corrections are made to the carving.

UNESCO: Culture

From 1819 to 1843, Truro's postmistress was a Miss Thomas, who preferred the use of blue ink instead of the normal black stamping.

BBC: Rare Truro blue marked letter found in Exeter archive

Outside a polling station in the wealthy suburb of Petionville, Zephyr Watson(ph) shows his thumb which was dipped in blue ink when he voted half an hour before.

NPR: Haitians Flock to Vote in National Elections