"His high fever attested to his illness"
"The buildings in Rome manifest a high level of architectural sophistication"
"This decision demonstrates his sense of fairness"
"I am licensed to practice law in this state"
"certified grade AAA meat"
We can certify for her competence as a secretary.
我们可以保证她能胜任此秘书工作。
Can you certify for his ability as a teacher?
你可以保证他能胜任老师的工作吗?
I can certify to his good character.
我可以证明他品德好。
I believe it to be true, but I am not able to certify to that effect.
我相信它是真的,但我不能证实其真实性。