An acid solution is concentrated when it has very much acid in it. 當酸溶液里含有很多酸時，它就被濃縮了。
"A science fiction cannot not be regarded as a mere entertainment, but in fact it tells the reader much more." "科幻小說不能簡單地看成是供消遣的，而實際上它給讀者展示更深刻的內容。"
She soaked the etching in an acid bath. 她將銅版畫浸入到酸性溶液中。
And, as anyone who has studied chemistry at school knows, if you drop chalk into acid it fizzes away to nothing. 並且，凡是學過化學的人都知道，把粉筆放到酸性溶液中，粉筆就會嘶嘶作響消失殆盡。
