癌细胞与正常细胞相比,数量增加最多的细胞器可能是[ ]
A.中心体
B.内质网
C.核糖体
D.高尔基体
答案:C
I found Tom ____ Chinese in the park when I went to look for him. [ ]
A. reads
B. read
C. reading
D. is reading
用分光光度法测量锌标准溶液,吸光度读数为0.7,比色皿长度为2cm,摩尔吸光系数为1.3×104,求锌标准溶液的浓度