2 sentences

1. 这种永不言败的精神，正是他走向成功的关键。

   zhè zhǒng yǒng bù yán bài de jīng​shén, zhèng​shì tā zǒu​xiàng chéng​gōng de guān​jiàn.

   This never-say-die spirit is precisely the key to his success.

   Source: Dong Chinese Dictionary

2. 刚才在门口敲门的那个人，正是我们要找的老师。

   gāng​cái zài mén​kǒu qiāo​mén de nà gè rén, zhèng​shì wǒ​men yào zhǎo de lǎo​shī.

   The person knocking on the door just now is exactly the teacher we are looking for.

   Source: Dong Chinese Dictionary