litmus blue

基本解釋

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(lán)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.
把管內(nèi)的氫氧化鈉殘液倒入水中，你就會(huì)發(fā)現(xiàn)：溶液會(huì)使紅色石蕊試紙變藍(lán)。
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.
這種變化雖然不同于堿滴定酸時(shí)石蕊由紅到藍(lán)的突然轉(zhuǎn)變，但也相差不遠(yuǎn)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