根据所学课文内容在每个空白处填入一个恰当的词。
In ten minutes I had seen all that could be seen in the fish, and started to look for the professor—who had, however, left. Half an hour 61—an hour—another hour; the fish began to look disgusting. I 62 it over and around; looked it in the face—ghastly; 63 behind, beneath, above, sideways—just 64 ghastly. I must not use a magnifying glass, 65 instruments of any kind. Just my two hands, my two eyes, and the fish: it seemed a most limited field of 66. With a feeling of desperation again I looked at that fish. I pushed my finger down its throat to feel how 67 the teeth were. I began to count the scales in 68 rows, until I was convinced that was nonsense. At last a happy thought 69 me—I would draw the fish; and now with surprise I began to discover new 70 in the creature. Just then the professor returned.