主动语态：
观察某人做某事
She observed him enter the bank.
They observed the stars twinkle in the night sky.
注意到某种情况或动作
I observed a strange noise coming from the basement.
The scientists will study the variety of trees and observe which are fruiting.
被动语态：
某人被观察到做某事
He was observed to enter the bank with a shotgun.
A man was observed to be going into the bank.
注意到某种情况或动作
The woman was observed to follow him closely.
She was observed to be asleep when I entered the room.
建议：
在使用“observe”时，可以根据具体的语境选择主动语态或被动语态，以确保句子的准确性和流畅性。
主动语态通常用于描述有意识的行为或观察，而被动语态则用于描述无意识或强制性的行为。
希望这些例句能帮助你更好地理解和使用“observe”这个词。