A.few people know | B.no one knows |
C.most people know | D.all the people know |
A.消亡 | B.丢失 | C.消失 | D.丧失 |
A.your eyes are poor |
B.you move it close to your eye |
C.its image falls on the blind spot |
D.your left eye is not open |
A.d. f. a. b. c. e. | B.a. c. f. d. e. b. |
C.f. a. d. c. b. e. | D.f. d. a. c. e. b. |
A.there is a blind spot in the eye |
B.an interesting experiment |
C.where the blind spot is |
D.how to find the blind spot |