Kuomintang and Communists united to fight against Japan during the Second World War.
Cantonese
国民党同共产党同意休战，一齐对抗日本入侵。
國民黨同共產黨同意休戰，一齊對抗日本入侵。
Kuomintang and the Communist Party agreed to temporarily stop the civil war and resisted the invasion from Japan together.
Examples (Wiktionary)
Mandarin
总括先生来信的意思，大概有两点，一是骂史太林先生们是官僚，再一是斥毛泽东先生们的“各派联合一致抗日”的主张为出卖革命。
總括先生來信的意思，大概有兩點，一是罵史太林先生們是官僚，再一是斥毛澤東先生們的“各派聯合一致抗日”的主張為出賣革命。
zǒng kuò xiān sheng lái xìn de yì si ， dà gài yǒu liǎng diǎn ， yī shì mà shǐ tài lín xiān sheng men shì guān liáo ， zài yī shì chì máo zé dōng xiān sheng men de “ gè pài lián hé yī zhì kàng rì ” de zhǔ zhāng wéi chū mài gé mìng ．
I take it that the main drift of your letter is contained in these two points: You consider Stalin and his colleagues bureaucrats, and the proposal of Mao Zedong and others — “Let all parties unite to resist Japan” — as a betrayal of the cause of revolution.
Mandarin
抗日战争
抗日戰爭
kàng rì zhàn zhēng
"War of Resistance Against Japan" (the Second Sino-Japanese War)
(China's) War of Resistance against Japan (1937-1945)
Mandarin
我们将和所有愿意抗日到底的阶级、阶层、政党、政团以及个人，坚持统一战线，实行长期合作。
我們將和所有願意抗日到底的階級、階層、政黨、政團以及個人，堅持統一戰線，實行長期合作。
wǒ men jiāng hé suǒ yǒu yuàn yì kàng rì dào dǐ de jiē jí ， jiē céng ， zhèng dǎng ， zhèng tuán yǐ jí gè rén ， jiān chí tǒng yī zhàn xiàn ， shí xíng cháng qī hé zuò ．
We shall persevere in the united front and practice long-term co-operation with all those classes, strata, political parties and groups and individuals that are willing to fight Japan to the end.
Mandarin
这是国民党一个绝大的错误，我们希望它在抗日的洗礼中改正这个错误。
這是國民黨一個絕大的錯誤，我們希望它在抗日的洗禮中改正這個錯誤。
zhè shì guó mín dǎng yī ge jué dà de cuò wù ， wǒ men xī wàng tā zài kàng rì de xǐ lǐ zhōng gǎi zhèng zhè ge cuò wù ．
This is a gross blunder, which we hope the Kuomintang will correct in the cleansing flames of the anti-Japanese war.