litmus blue

基本解释

Besides having a sour test , acids change the colour of litmus from blue to red.
除了有酸味以外，酸還能使石蕊由藍色變成紅色。
tsunzhi.blog.163.com
Turn the remnant of sodium hydroxide in the tube into water, and you'll find the solution turns red litmus blue.
把琯內的氫氧化鈉殘液倒入水中，你就會發現：溶液會使紅色石蕊試紙變藍。
www.poetic.com.cn
It was not quite the sudden shift from litmus red to blue of an acid being neutralised by an alkali, but it was not far off.
這種變化雖然不同於堿滴定酸時石蕊由紅到藍的突然轉變，但也相差不遠了。
blog.sina.com.cn

It was not quite the sudden shift from litmus red to blue of an acid being neutralised by an alkali, but it was not far off.
ECONOMIST: Ecology raids the techniques of chemistry