Is it true that when you are in a discussion you have to agree before you disagree? and why do you have to do so?

In a sense, yes. One must agree before you can start to disagree.

You must agree to:

1) The topic you guys are talking about. Two different topics discussed at the same time can lead to problems

2) The Facts: The facts are key in a discussion, and are generally used in debates and arguments. Each person must agree that what is stated is a fact.

3) You'll have to agree that there is a problem, and that a solution can be found. You are only disagreeing on how to get the solution.

hope this helps

the sentence does not violate the phrase structure second rule (introduced by noam chomsky) because noun phrases consist of a determiner such as a, the or every, and a noun. in the sentence, the noun phrase the cake includes a determiner (the) and a noun (cake).

on the other hand, the first rule indicates that a sentence encloses a noun phrase, followed by a verb phrase. the example sentence can be analysed as follows:

john (n) + ate (v) + the (det) + cake (n).

onto a large boat, and mark the water level that the boat sinks to. then, take the elephant out and put a bunch of marked weights onto the boat until it reaches the same water level. add up the masses of the weights to get the weight of the elephant.