Grammar
The Subject of the sentence is the pronoun "I". The Predicate is:
- don't want to know how you did it.
The Head of the verb phrase is the word don't, which is contraction of the dummy auxiliary verb do and the negative particle not. This takes as its Complement the verb phrase:
- want to know how you do it.
The Head of this verb phrase is the verb want. The word want takes as its Complement the infinitival clause:
The Head of his phrase, depending on your grammar, is probably the verb know (some writers would argue the Head is the word to). The word to in this case is a subordinator which marks know how you did it as subordinate. The verb know takes as its Complement the interrogative finite clause:
The Subject of this clause is the pronoun you. The Head of the clause is the verb did. The Direct Object is the pronoun it. The clause has an Adjunct, the interrogative adverb how, which has been fronted to the beginning of the clause.
The verb want is a control verb. This means that if there is no expressed Subject of the following infinitive clause, we understand the Subject of want to be the Subject of the following infinitive. So the sentence can be interpreted like this:
- I don't want [ (me) to know how you did it ].
Meaning
Suppose the listener has done something. Maybe they stole some jewels from a museum and nobody caught them. To do something like this, the listener would need to use some kind of plan or method. This is what is expressed by:
The word how refers to the method used. The speaker is telling the listener "I do not want to know the method!". Of course we don't know what the listener actually did. It might be something quite boring.
'Cause' in the sentence given is neither noun nor adjective, it's verb.
To understand this try answering your question - This will cause the problems like .... to the individuals and to the society.
cause (noun) - the reason behind some action.
Examle: The cause of our country's plight is corruption.
Or as you asked use of be look at this:
Corruption is the cause of our country's plight.
to cause (verb) - to make something happen.
Lack of exercise causes ill health.
https://dictionary.cambridge.org/dictionary/english/cause
Best Answer
I want to go buy a gift.
"to go" and "to buy" are verbs, of course. The sentence is a shortened form of "I want to go and buy a gift/present". You could also say: I want to go (in order) to buy a present.