All but Dick _______ in Class Three this term. [ ]
A. are
B. is
C. were
D. was
答案:A
杆状细胞对光刺激极敏感(感光),但完全不感色;锥状细胞的感光能力比杆状细胞差得多,但他们能对各色光有不同的感受。因此锥状细胞的存在,决定了分辨颜色的能力——()
Flash允许用户把()、数据、图像、声音和脚本交互控制融为一体。