Key words and grammar:

1, in this question, the main interrogative word is "How long", which means "how long" and the length of time. Such as:

——How long have you been employed at this job

How long have you been employed for this job?

It should be noted that "How long" does not mean how long it is in "distance". If you want to express the "how long" of the distance, you need to use the interrogative word "How far". For example:

——How far can you throw the stone?

How far can you throw the stone?

2. In this question, we can find that the components in the sentence "will it take" are: modal verb+subject+predicate. This is because in special interrogative sentences (interrogative words (+nouns)+general interrogative sentences) (or in declarative sentences), will needs to be placed before the subject. Such as:

——What books will you take with you?

Do you need to bring any books?

There is another situation: if it is a general question (question word (+noun)+predicate), will is placed after the subject. Such as:

——Whose house will be pulled down?

Whose house will be demolished?

Extended data:

Perhaps we can better understand the meaning of the sentence "How long will it take" and its usage context through examples:

1、How long will it take to collect domestic garbage along a main street

How long does it take to collect domestic garbage on a main road in a city? ?

Analysis: "How long will it take" is the main part of the question, followed by "to collect", where "to" means the purpose.

2、It has set us back in so many respects that I'm not sure how long it will take for us to catch up ?

This has caused us delays in so many ways that I'm not sure how long it will take us to catch up.

Analysis: The key part here is "how long it will take". It can be found that the word "will" is placed after the subject "it", because this sentence is a general interrogative sentence (or declarative sentence), and according to grammar, will should be placed after the subject.