The definition of “ building work ” contained in Rule 2.2 clearly indicates that a person seeking enlistment as Class-I contractor mandatorily needs to demonstrate that he is, as on the date of his application, having the requisite experience of having completed works of the nature contained in Rule 2.2. In other words, the person should have commenced and successfully completed construction of a residential or non-residential structure, consisting of foundation, walls, floors, roofs, finishing, civil and electrical services, complete, executed under a single contract with E&M component. It brooks no ambiguity that a person seeking enlistment as Class-I contractor must necessarily have commenced and completed the aforesaid works mandatorily to be entitled to apply for such enlistment. Additionally, Rule 2.2 also contains specifications in regard to works which fall within the definition of “ building works ” apart from the above civil works, which may include electrical installations, electrical and mechanical services of buildings etc. To us, it is clear that the second part of the Rule 2.2 is secondary whereas, the first part regarding civil construction work is primary in nature. Thus, to be eligible, a person must