使必要用英语怎么说？

使必要

Make necessary

例句

• Humate - P provides a preventive therapy that can make needed surgery not only possible, but also safer. 作为预防措施,精制灭菌冻干人抗血友病因子不仅使必要的手术成为可能, 也使其更安全.
• He held himself ready to bestride the animal at a moment's notice , should flight become necessary. 象童本人做好准备,假使必要的话,他就立刻跳上大象逃走.