用because,busy,strict,tired,fun,interesting,boing,difficult,relaxing...答: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 ...