Even though the main source of ______ exposure for a majority of the human population is the sun, the artificial tanning from sun beds contributes significantly to the total UV risk.
【简答题】新进阶大学英语第二册 U2 Language Quiz There are ten sentences in this section. Beneath each sentence there are four words or phrases marked A, B, C and D. Choose one word or phrase that best completes the sent...
【简答题】U2 Additional Language Quiz There are ten sentences in this section. Beneath each sentence there are four choices or phrases marked A, B, C and D. Choose one word or phrase that best completes the sen...