They observed him entering the bank.

他们看见他走进银行。

《牛津词典》

After a pause, his brother said to the servants, "You have observed him."

歇了一会儿，他弟弟对仆人们说：“你们已经看到他了。”

youdao

While he was at work, a gendarme passed, observed him, and demanded his papers.

正在他工作时，有个警察走过，注意到他，便向他要证件。

youdao

He said the idea came to him when he observed that the coasts of South America and Africa could fit together like two pieces of a puzzle.

VOA: special.2010.01.12

But Pavlov observed that when somebody entered the room who typically gave him the food powder, the dog--the food powder saliva would start to come out.

他注意到,当给它喂食的人,进屋时，狗便开始分泌唾液。

耶鲁公开课 - 心理学导论课程节选

Bobby Valentine is one of the smartest baseball minds of our time according to many that have worked with, played for, or observed him at his craft.

FORBES: Bobby Valentine's Firing in Boston: A Lesson in Failed Organizational Leadership at Fenway

Indeed a behaviourist who observed Sinclair recognised him to be affable and polite, even during police interviews.

BBC: NEWS | UK | Scotland | Edinburgh, East and Fife | A life of abuse, rape and murder

As many others have observed, Drucker never lost his interest in the changing world around him.

FORBES