问题补充：
Well its been up here two and a half years now,its an infra-red detector that senses the earths temperature with great accuracy ,中的it is been 这在语法上怎么解释阿,请前辈指点,
答案：
its been up here= Its has been up here.
its = it is/ it has
要学会自己去判断.
======以下答案可供参考======
供参考答案1:
哦，它在这里已经两年半的时间了，它是一台红外线监测仪，可以非常精确地感知地球的温度。 its been up 完全形式是：It has been ,
供参考答案2:
这要根据语境去理解，比如上文中的 its been up here是指 来此
供参考答案3:
这是在两年半的时间，现在，它的红外线检测器，检测地球的温度与伟大的准确性，（中的是它了）
