litmus

n [U] blue colouring-matter that is turned red by acid and can be turned blue again by alkali 石蕊（蓝色物质, 遇酸变红, 再遇硷则还原变蓝）.

liter, literacy, literal, literally, literalness, literary, literate, literati, literature, lithe, lithium, litho, lithograph, lithographic, lithography, lithosphere, litigant, litigate, litigation, litigious, litmus paper, litotes, litre, litre (US liter), Litt D, litter, litter basket, litter-basket, litter-bin, litter-basket, litter-lout, little, little by little, Little Rock, little-appreciated, littoral, liturgical, liturgically, liturgy, livable, live,