- 準關係代名詞：用法跟that很像，但是先行詞要有the same…或such…
- As it’s a long journey, I packed snacks and drinks for the trip.
- As the weather is nice, let’s have a picnic in the park.
- I’m studying hard as I want to pass the exam.
- As the store is closed, we’ll have to come back tomorrow.
as的語意是當…時，用法跟語意和when跟while相近，用於表示某事與另一件事同時發生。在這個語意下，有一個常見片語是just as，語意強調兩個動作或事件恰好同時發生(兩件事非常密切地同時發生)。下面舉例說明as跟just as的分別：
As she left, my phone rang.
Just as I was about to leave, my phone rang.
- As I was studying for my exam, I listened to classical music to help me focus.
- As the storm approached, we quickly shut the windows.
- As we were hiking, we came across a beautiful waterfall.
- As the clock struck midnight, the New Year began.
- Her face blushed as she thought of it.
- As the train arrived at the station, I realized I left my phone at home.
- Just as the concert was ending, the power went out.
- Just as I was about to take a bite of my sandwich, the doorbell rang.
- As the game was going on, the crowd was cheering loudly.
- As the sun set, the sky turned a beautiful shade of orange.
- As the meeting progressed, the discussion became more heated.
- As technology advances, the way we live and work is constantly changing.
- As the nation grew, so did what came to be called the American Dream.
Though it was raining, I went for a walk.
-Raining as it was, I went for a walk. 雖然下著雨，我還是去散步
Though she worked hard, she did not get the promotion.
-Hard as she worked, she did not get the promotion. 儘管她工作很努力，但她沒有得到晉升
Though he is a child, he has a mature understanding of the world.
-Child as he is, he has a mature understanding of the world.雖然他是個孩子，但他對這個世界有著成熟的認識
- Tired as I am, I will stay up to finish this project.
- Angry as he was, he spoke to his son calmly.
- Fast as he ran, he still couldn’t catch up with his competitors.
- Girls as they are, they still enjoy playing with trucks and cars.
- As you said, he did not believe me.
- She did as she was told.
- As I was just saying, I think we should consider a different approach.
- He was late, as usual.
- As with all book covers, good design is vital.
- Father will need to rest as well.
- As soon as I finished my exam, I went to see my friends.
- The boy was very tall–as tall as an adult.
- She had to get a car as soon as possible.
- She swims as fast as a fish.
- He doesn’t play games as much as he used to.
as也可以當關係代名詞，只能構成形容詞子句。他的用法跟that當關係代名詞很像，可以代替人或是物，但是先行詞必須是the same + 名詞，或是such +名詞。進一步理解請閱讀『as, but, than當準關係代名詞的用法解析與例句』。
- He has the same book as you.
- The dress she wore to the party was the same as mine.
- As is often the case, the weather forecast was wrong and it rained unexpectedly.
- As is often the case with human emotions, it’s hard to predict how someone will react.
- As is often the case in large organizations, communication can be a challenge.
as還有介系詞的用法，它的語意是身為，作為…的身份。很多人將它跟like混淆，like當介系詞的的語意是像。She is like a teacher.她像個老師，但，事實上，她不是。She works as a teacher.她是老師。
- He was chosen as captain because of his leadership skills.
- She moves as gracefully as a dancer.
- As a student, I spend most of my time studying.
- The city is known as a cultural hub.
- He worked as a waiter when he was a student.
- A coin can been used as a key to this door.
- Van Gogh was regarded as one of the greatest painters of his time.
- The company regards its employees as its most valuable asset.