now that和 seeing that引导原因状语从句,都不是最直接的原因，可以译为“既然，鉴于，由于、因为等”，但是，它们是有区别的：
1、 now that比较多用于口语；seeing that多用于书面语；
2、 now （that）除用于表示原因外，还可以表示时间。
3、 下面通过一些经典例句来进行学习和提高：
Now that everybody is here, let's begin our meeting.
既然人都到齐了,我们就开会吧。
Now that the problem is solved, nothing remains to be said.
问题已经解决了，没什么说头儿了。
Now that a decision has been taken, let each one do his job.
既然决定了，就分头去办。
Now that you mention it, she did seem to be in a strange mood.
既然你说到这事儿，她确实好像情绪不大对。
Now that you are here, you'd better stay.
既然你已经来了，最好还是住下。
Now that he is back, the prime minister has another chance to put his new ideas into practice
既然首相又掌权了，他就重新有机会实施他的新想法。
Now that he has become President, many people once again have hope for genuine changes in the system
既然他已当上了总统，很多人又再次看到了进行真正的体制改革的希望。
Now that the problem has been identified, appropriate action can be taken.
现在既已找出问题的症结，即可采取适当行动。
They are hoping for a return to normality now that the war is over.
既然战争结束了，他们希望一切都恢复常态。
Now that the highway is finished, the shopping centre should thrive/ flourish/ prosper.
既然这条公路已经竣工，那个商业中心一定会兴隆起来。
Now that Chris is gone she wants me to step into his shoes.
既然克里斯走了，她就想让我接替他的位置。
Now that Tony was no longer present, there was a distinct change in her attitude
由于托尼不在场了，她的态度有了明显的转变。
Now that we are all part of the global village, everyone becomes a neighbour.
既然我们都是地球村的一部分，大家都成了邻居。
now （that）除用于表示原因外，还可以表示时间：
Now that she was retired she lived with her sister.
现在她已经退休了，和姐姐一起住。
Now that the initial shock was wearing off, he was in considerable pain
最初的震惊渐渐过去之后，他感到疼痛难忍。
I only wish he were here now that things are getting better for me
现在我的境况好转了，我真希望他能在这里。
How do you fill your day now that you've retired?
现在你已退休了，怎样打发你的日子？
Now that the kids have left home we've got a lot of extra space.
孩子们都离开家了，我们住着就更宽绰了。
Now that their children have grown up she joins Paddy in London every other week.
他们的孩子都长大了，她便每隔一周就到伦敦帕迪那里。
Now that Fantina is old, she has been cast aside like some useless object.
范蒂娜如今老了，像废物一样被丢在一边。
I realise now that the things which used to niggle and annoy me just don't really matter
我现在意识到那些曾令我烦恼不快的事情其实无关紧要。
Now that she's a flight attendant, foreign travel has lost its glamour for her.
她现在是空中乘务员了，去国外旅行对她已失去吸引力。
seeing that经典例句赏析（通用语considering that）：
Seeing that she got the hint, she's quite smart.
她明白我的暗示，挺聪明的。
Seeing that he is ill, we'll do the work for him.
由于他病了，我们来代他做这件工作。
Seeing that he's ill, he's unlikely to come.
他既然有病，那就不大可能来了。
Seeing that we had noticed him, he moved off quickly.
因为看见我们已注意到他，他就赶快走掉了。
Seeing that things were going against him, he took to his heels.
他一看形势不对，拔腿就跑。
He has done well to pass his exams, seeing that he has been ill a lot,
鉴于他经常生病，考试能及格就很不错了。
Seeing that he's been off sick all week he's unlikely to come.
他请病假整整一周了，所以今天也不大可能来。
Seeing that nobody was very enthusiastic about it，they decided to cancel the trip．由于没有人有此热情，他们决定取消这次远足。He has done well to pass his exams，seeing that he has been ill a lot．考虑到他多次生病，他考试能及格就很不错了。
Considering that he received no help, his results are very good. 考虑他没有获得任意协助，他的成效要算作非常好的了。
Considering that you are no longer involved with this man, your response is a little extreme.
考虑到你已经与这个男人划清了界限，你的反应有一点儿过头。
Considering that the government's standards are not nearly ambitious enough, the picture is clear: by not cooking at home, we're not eating the right things, and the consequences are hard to overstate.
考虑到政府的标准还不够远大，实际情况变得很明确：不在家做饭，我们无法吃到对的东西，因而很难夸大后果。
