Zài lǎoshī de bāngzhù zhīxià, tā jìnbù hěnkuài.
Under the teacher's guidance, he improved quickly.
Zài yālì zhīxià, tā zuòchū le cuòwù de juédìng.
Under pressure, he made the wrong decision.
Bǐjiào zhīxià, zhège fāng'àn gèng hǎo.
By comparison, this plan is better.
