一般需要特指的时候会用到the，比如He is the man I am waiting for. 这个定语从句修饰特指的那个man（那个man，the man）.通常情况下，如果你要提及的东西不唯一，而你又想指明其中某一部分时，你就需要用the。比如： There are many men, but the man I am waiting for is absent. 缺席的是特指那个我正在等待的男人。那里有很多男人，我想说的是那个我在等待的男人。再比如：they are dogs I have taken cared of. 有时候你可能会在电影里面看到某人指着另外一个人说 "He is the guy!"，就是那个家伙！ 一般来说，如果一个东西不唯一，而你只是提及其中部分而非整体时，就需要用the，当然也有例外，比如地球只有一个，但是还是会说the earth，on the earth 在地球上。（也有on earth，但是这里意思完全不一样，你可以查一查），当然这些例外很少。

I'm confused as to why you think that adding 'the' will make the sentences more emphatic. Where did you learn this? Your first sentence is OK (although 'build up inspiration is a little unnatural). 'Curiosity' is an abstract and uncountable noun, so it does not take an article. Your second sentence is odd - and as a standalone statement, it's wrong. It begs the question 'What curiosity?'. If you use a definite article, it means that we are referring to a particular curiosity, which is a strange concept. The only way that 'the curiosity' could be correct is if you were to define it, for example: It is the curiosity which their teachers instilled in them that enables them to build up adequate inspiration. Admittedly, this makes for a clumsy sentence, but the added relative clause ' which their teachers instilled in them' is necessary because it defines 'the curiosity'. It makes the distinction between this particular 'curiosity' (perhaps about science) and other types of curiosity. Perhaps you should check in your grammar book again about the function of the definite article. When you use 'the', the reader or listener has to know which 'thing' you are talking about - but with a concept such as curiosity, this doesn't really work. The definite article makes the noun SPECIFIC, not emphatic. Emphasis is a different idea entirely.

Either way is correct. Adding "the" will put a little more emphasis on the next word "curiosity." However, adding "the" will often make your sentence wrong / sound unusual if not used correctly. It depends on the previous sentence.

Hi Shellmy, I think that I understand your question, but could you use a different sentence? The sentence you have provided is very unusual.