“Strangely enough, I just bought a bike. You're welcome to have my old one.”
You're chatting with a neighbor. He says that he crashed his bicycle. You just bought a new bicycle, so you're not using your old one. You offer to give your neighbor your old bike.
Strangely enough, I just bought a bike. You're welcome to have my old one.
One of the uses of "just" is to express that something happened very recently. It can mean a few minutes before:
I'm sorry, he just walked out to go get lunch.
Or immediately before:
What did he just say?
Or it can mean a few years:
Mankind has just started to study ways to understand and control DNA.
But in any case, "just" means a short time before.
This is a way to offer something to someone:
You're welcome to use my car if you need to go anywhere.
You're welcome to come with us if you want to.
Offering things in this way is friendly and low-pressure. In other words, it doesn't make the listener feel like they have to accept the offer.
Use this phrase when something surprising or coincidental happens. For example, if a friend tells you that she recently got a new job, and you also got a new job recently, you can respond:
Strangely enough, I just started a new job last week!
Another example: someone asks you whether you've spoken to your brother lately. Usually you speak with him every week, but the last time you spoke to him was 3 weeks ago. You can say:
Strangely enough, no. I haven't heard from him for a few weeks.
"Bike" is short for "bicycle":
I never learned how to ride a bike until I was in my teens.
Sometimes people also call motorcycles "bikes":
Where did you park your bike?
Usually you can guess based on the situation whether someone is talking about a bicycle or a motorcycle.