GL-5 Gwoyeu Row -u- Finals 國語羅馬字 ㄨ 行韻母的標調法

In Gwoyeu Luomaatzyh (Gwoyeu Romatzyh, National Romanization), most row -u- finals show tone by changing the medial vowel (u, w, o = 1st, 2nd, 3rd tone), rather than adding a letter so they are printed in green. 

Gwoyeu Luomaatzyh -u- Row Finals (How to Show Tones) 國語羅馬字 -u- 行韻母的標調法

國語羅馬字 ㄨ 行韻母大部分都是靠韻母的改拼來標調 (u、w、o = 一、二、三聲), 因此印成綠色。

GL-4 Gwoyeu Row -i- Finals 國語羅馬字 ㄧ 行韻母的標調法

In Gwoyeu Luomaatzyh (Gwoyeu Romatzyh, National Romanization), most row -i- finals show tone by changing the medial vowel (i, y, e = 1st, 2nd, 3rd tone), so they are printed in green (environmentally friendly :-). There are a few special cases, however. For example, the medial vowel in解can not be changed to -e- because jee = 者 (zhě in HP), so the last letter is doubled: 解 = jiee is the correct spelling (jiě in Hanyu Pinyin, HP).

國語羅馬字 ㄧ 行韻母大部分都是靠韻母的改拼來標調 (i、y、e = 一、二、三聲), 因此印成綠色（比較環保哦！），不過有幾個特殊例子。譬如說，『解』的介音 -i- 不能改拼成 -e- （這樣會產生jee = 『者』，漢語拼音 = zhě )，只好在尾音 -e 之後加個 e：解 = jiee 才是正確拼法 (漢語拼音 = jiě)

Gwoyeu Luomaatzyh -i- Row Finals (How to Show Tones) 國語羅馬字 -i- 行韻母的標調法

GL-3 National Romanization-- Keep, Change, Add! 國語羅馬字：留、改、加！

Variations of the base form (initial, medial and final) of National Romanization are used to spell the four tones of mandarin Chinese. Words spelled in National Romanization (Gwoyeu Luomaatzyh) have distinctive shapes which are easy to recognize. This is especially helpful for foreigners struggling to learn the four tones of Mandarin Chinese. 國語羅馬字靠基本形式（聲母、介音、韻母）的不同拼法來表示漢語的四聲。『留、改、加』這三個原則使『國羅』拼出來的字，個個有其獨特風貌、易於辨認。對於外國人學習國語的聲調非常有幫助。

1 Keep留: Keep the unchanged base form; Use it to spell most first tone words and all second tone words starting with m-, n-, l- or r. 保留基本形式，用來拼寫一般陰平（一聲）字及ㄇㄋㄌㄖ開頭的陽平（二聲）字