1. I want to be an architecture designer in the future.

2. I want to be an architectural designer in the future

3. I want to be a construction designer in the future.

4. I want to be a constructional designer in the future.

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Which one is grammatical and commonly used?

2.I want to be an architectural designer in the future

Out of the four sentences you provided, the most grammatically correct and commonly used sentence is:

2. I want to be an architectural designer in the future.

This sentence is grammatical because it uses the correct modifier "architectural" to describe the type of designer you want to be. "Architectural" specifically relates to the field of architecture and design.

However, it is worth noting that the term "architectural designer" can have slightly different meanings depending on the context. Generally, an architectural designer is someone who works on the design aspects of architectural projects, but does not necessarily have the same qualifications or certifications as a licensed architect. If you aspire to become an architect with full certification, you may want to consider using the term "architect" instead.

Sentence 1 is not grammatically correct because "architecture designer" should be corrected to "architectural designer" for proper phrasing.

Sentences 3 and 4 are not commonly used, and both contain grammatical errors. "Construction designer" is not a commonly recognized term in the field of design or construction. Instead, the term that is mostly used is "architect" or "architectural designer" to refer to professionals in the architectural and construction design industry.

In summary, sentence 2 is the most grammatically correct and commonly used statement out of the four options, expressing your aspiration to become an architectural designer in the future.