Three or four months should be enough for the project definition phase.

三到四个月对于项目定义阶段应该足够了。

youdao

It is important to involve the users in the definition phase, design phase and in the testing of the project result.

在项目定义阶段，设计阶段，和结果测试阶段，用户的参与是很重要的。

youdao

Since development is an iterative process, requirements definition does not end in the initial project-definition phase.

由于开发是个迭代的过程，所以需求定义并没有终止在初始的项目定义阶段。

youdao

The completion of the so-called System Requirements Review and System Definition Review allows program managers to proceed into the rocket's preliminary design phase, NASA officials said.

MSN: Giant deep-space rocket passes key test - Technology & science - Space - Space.com | NBC News