1·Such measures are desirable, if not essential.
这些措施即使不是必要，也是可取的。
—— 《牛津词典》
2·Yeast is essential for the fermentation that produces alcohol.
酵母对酿酒的发酵是必要的。
—— 《柯林斯英汉双解大词典》
3·Although not essential, some prior knowledge of statistics is desirable.
统计学的知识虽非必要，但最好是学过一点。
—— 《牛津词典》
4·We know fidelity is an essential principle of genetic transmission.
我们知道，准确性是基因传递中的一个必要原则。
5·It is essential that people understand the potential problems of cross-cultural communication.
人们有必要去了解跨文化交流中存在的潜在问题。