根据题意得:x-6≥0,
解得:x≥6.
Mr. Black rewarded the girl _____ $20 _____ bringing back the lost wallet. [ ]
A. with, for
B. for, with
C. at, of
D. for, for
煎药容器以砂锅、搪瓷器皿为好,忌用铁器,以免发生物理反应。