本期内容：

The White House said that it would ask Congress for $1.8 billion to combat Zika, to be spent on vaccine research, mosquito control and other efforts. In America, around 50 people recently returned from affected regions have been diagnosed with the mosquito-borne virus; one instance of sexual transmission was recorded in Texas last week.

词义解析:

Combat: 与……战斗
Vaccine：疫苗
Affected region: 疫区
Diagnose: 诊断
Instance：病例
Sexual transmission：性传播