用because,busy,strict,tired,fun,interesting,boing,difficult,r

请问：楼主打的“boing”是不是打错了?是不是“boring”?
He didn't go to school,because he was ill.他没去上学,因为他病了.
He didn't come here yesterday,because he was busy.他昨天没来,因为他很忙.
Our teather is strict with us.我们的老师对我们要求很严格.
Let's have a rest,I'm very tired.让我们休息一下吧,我很累了.
They have had fun yesterday.他们昨天玩得很开心.
This game is very interesting.这个游戏很有趣.
He said this book is very boring.他说这本书很无聊.
It is difficult to learn French for me.学法语对我来说很难.
I think swimming is relaxing.我认为游泳能使人感到轻松.
希望能帮上您