1.be useful to_ 2.be helpful to3.be important to4.be necessary to填doing或do

分类: 作业答案 • 2022-06-12 09:42:56

问题描述：

1.be useful to_______ 2.be helpful to______3.be important to______4.be necessary to______
填doing或do

答

1.be useful to_______ 2.be helpful to______3.be important to______4.be necessary to______填doing或do