经过多次实地调查,研究团队确信污染源来自上游工厂。Jīngguò duō cì shídì diàochá, yánjiū tuánduì quèxìn wūrǎnyuán láizì shàngyóu gōngchǎng.After several field investigations, the research team was convinced that the pollution source came from an upstream factory.
我确信这次考试发挥了正常水平。Wǒ quèxìn zhè cì kǎoshì fāhuī le zhèngcháng shuǐpíng.I am convinced that I performed at my normal level in this exam.
她确信自己选对了专业,从不后悔。Tā quèxìn zìjǐ xuǎn duì le zhuānyè, cóng bù hòuhuǐ.She was firmly convinced she had chosen the right major and never regretted it.