PHRASAL VERB 为…逐步做准备 If you build up to something you want to do or say, you try to prepare people for it by starting to do it or introducing the subject gradually. 为…逐步做准备
Other actions we need to take may be more difficult, and we may have to build up to them gradually. [VERBPREP.PREP. noun]
我们需要采取的其他行动可能会更加困难,我们将不得不逐步做准备。
Carl was building up to something. [VERBPREP.PREP. noun]