What Is The First Step Of The Hydrogen Fusion Process? ${ }_1^1 H +{ }_1^1 H \rightarrow{ }_1^2 H + E ^*+ V +$ Energy ${ }_2^3 He +{ }_2^3 He \rightarrow{ }_2^4 He +2\left({ }_1^1 H \right)+$ Energy ${ }_1^2 H +{ }_1^1 H \rightarrow{ }_2^3 He +$

以下是一些例句： the first step is to gather your materials. Firstly, let's discuss the budget. First of all, we need to identify the problem.

First 有多种词性，其中就有名词，剑桥词典对作名词的first的定义是：the first person or thing to do or be something, or the first person or thing mentioned，例句有： [ + to infinitive ] she was. First和firstly作副词时完全同义，都可以表示“第一，首先”，都可用作句子副词，此时first也可写作first of all。 例如： first，i would like to thank everyone for coming.