VOA原文：

The Biden administration is calling on people to exercise renewed caution about COVID-19, emphasizing the importance of getting booster shots for those who are eligible and wearing masks indoors as two new highly transmissible variants are spreading rapidly across the country.

拜登政府呼吁人们对新冠病毒再次保持警惕，强调注射加强针和室内佩戴口罩的重要性，因为两种新的高传染性病毒变种正在美国各地迅速传播。

1.The Biden administration 拜登政府

2.exercise renewed caution about sth 对某事再次保持警惕

3.get booster shots 注射加强针

4.highly transmissible variants 高传染性病毒变种

The new variants, labeled BA.4 and BA.5, are offshoots of the omicron strain that has been responsible for nearly all of the virus' spread in the U.S. and are even more contagious than their predecessors. White House doctors stressed the importance of getting booster doses, even if you have recently been infected.

标记为BA.4和BA.5的新变种毒株是奥密克戎毒株的分支突变，奥密克戎毒株可以说是让新冠在美国传播的最大罪魁祸首，BA.4和BA.5毒株甚至比它们的前身更具传染性。白宫的医生强调了注射加强针的必要性，哪怕民众最近已经被感染。

5.offshoot strain n. 分支突变（offshoot n. 分支，衍生物 strain n. （动植物的）品种；疾病的类型；菌株）

6.omicron strain 奥密克戎毒株

7.contagious adj. 具有传染性的

【拓展】

8.mutant adj. 突变的；因基因变异而不同的 n.突变体；突变异体怪物

例句：The quickly changing coronavirus has spawned yet another super contagious omicron mutant.

快速变化的新冠病毒又产生了另一种具有超级传染性的奥密克戎突变体。

9.the rates of transmission 传播率

例句：In India, the rates of transmission are showing kind of that exponential increase.

在印度，传播速度呈指数型增长 。