如何使用 "necessary" 造句

1. Political reforms are also necessary .
政治改革也很必要。
2. The necessary technology already exists .
必要的技术已经存在。
3. A lighter application was necessary .
化妆手法柔和颇有必要。
4. I believe that is necessary .
我认为这是必要的。
5. These large deficits are necessary to avoid deflation .
这种巨额赤字是避免通缩所必需的。