There are so many apples ___ that tree. [ ]
A. in
B. on
C. at
D. from
答案：B
卫生行业标准的符号是（）
A.GB，GB/T
B.GJ，GJ/T
C.JG，JG/T
D.BG，BG/T
E.WS，WS/T
斐克定律〔反应堆物理〕Fick’s law
