可是

汤姆给玛丽写了封长信，可是没有寄给她。

Tāng mǔ gěi Mǎ lì xiě le fēng cháng xìn， kě shì méi yǒu jì gěi tā。

Tom wrote Mary a long letter, but he didn't send it to her.

Tom写作可以写的像本国人一样，可是他的发音很烂

T o m xiě zuò kě yǐ xiě de xiàng běn guó rén yī yàng， kě shì tā de fā yīn hěn làn

Tom can write almost like a native speaker, but his pronunciation is terrible.