20

3. verify requirement: process of ensuring that expressed requirements lead to correct excecution. validate requirements: process of ensuring that the executed work correctly addresses the identified business need.

6. buy vs build? employ third party computing clusters as opposed to maintaining and running their own.

11. User can update requirement, developer can also update requirement (developer is a specialized user and has all the privileges that of a normal user)

21. Scalability: volume of requirement for the application

25. large并非specific