一个英文例句.It is regarded as one of the three quintessence of Chinese culture,the other two being traditional Chinese medicine and Peking Opera.其中的being是什么用法,为什么不是are?请高手指教,门外汉就不要误人子弟了

It is+时间段+since+时间点.可以说一个例句吗？ 一个英文谜语谜语 It is long.It is thin.It is green.What is it? something means a lot more it appears.的中文意思?并举一个英文例句! It is necessary to do 的例句 as it is 的意思和例句 英文an a的造句,三句 （老师给的例句是.It is an orange.） 中学英语学习中的一个小小语法点,不大懂,例句：I think it essential to reserve air tickets这一类句子中都用 it 作形式宾语请问：为什么这个例句不能改为“I think it is essential ... 感觉读来也挺顺啊. It is +adj for to do 的用法和例句 It is +adj+that的从句用法对了还要例句 it is found out是什么意思?另请举两个例句 请举个例句说明1.it is commanded that2.command doing 模仿例句作答,例句：the dog is clever it's a clever dog1、2、3、 一个英文谜语It's coming. It is always coming. But it never arrives. What's it? it is no good doing sth和it is no use doing 要例句 it is high time to 例句：It is high time to protect the animal it was only later是什么意思,给我一个例句 一个英文例句.It is regarded as one of the three quintessence of Chinese culture,the other two being traditional Chinese medicine and Peking Opera.其中的being是什么用法,为什么不是are?请高手指教,门外汉就不要误人子弟了 有一个例句是：It is not proper that you (should) wear a cap while eating.是不是这种It is proper that 句型接从句要用should加动词原形的虚拟语气．