题目内容

在眼底示意图中,不同的眼底表现用不同的颜色表示 玻璃体积血( )

A. 红色
B. 蓝色
C. 绿色
D. 黄色
E. 棕色

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Space is a dangerous place, not only because of meteors (流星) but also because of rays from the sun and other stars. The atmosphere again acts (67) our protective blanket on (68) . Light gets through, and this is essen- tial (69) plants to make the food which we (70) . Heat, (71) , makes our environments tolerable and some ultraviolet rays (紫外线 ) penetrate the (72) . Cosmic ( 宇宙的) rays of various kinds come (73) the air from outer space, but (74) quantities of radiation from the sun are screened off. As (75) as men leave the atmosphere they are (76) to this radiation; (77) their spacesuits or the walls of their spacecraft, if they are inside, (78) prevent a lot of radiation damage. Radiation is the greatest known danger to explorers in (79) . Doses of radiation are measured in (80) called "reins (霍姆)". We all 81 radiation here on earth from the sun, from cosmic rays and from radioactive minerals. The " (82) " dose of radiation that we receive each year is about 100 millirems; it (83) according to where you live, and this is a very rough estimate. Scientists have reason to think (84) a man can (85) up with far more radia- tion (86) this without being damaged; the figure of 60 rems has been agreed.

A. get
B. make
C. have
D. do

Space is a dangerous place, not only because of meteors (流星) but also because of rays from the sun and other stars. The atmosphere again acts (67) our protective blanket on (68) . Light gets through, and this is essen- tial (69) plants to make the food which we (70) . Heat, (71) , makes our environments tolerable and some ultraviolet rays (紫外线 ) penetrate the (72) . Cosmic ( 宇宙的) rays of various kinds come (73) the air from outer space, but (74) quantities of radiation from the sun are screened off. As (75) as men leave the atmosphere they are (76) to this radiation; (77) their spacesuits or the walls of their spacecraft, if they are inside, (78) prevent a lot of radiation damage. Radiation is the greatest known danger to explorers in (79) . Doses of radiation are measured in (80) called "reins (霍姆)". We all 81 radiation here on earth from the sun, from cosmic rays and from radioactive minerals. The " (82) " dose of radiation that we receive each year is about 100 millirems; it (83) according to where you live, and this is a very rough estimate. Scientists have reason to think (84) a man can (85) up with far more radia- tion (86) this without being damaged; the figure of 60 rems has been agreed.

A. but
B. because
C. so
D. for

Space is a dangerous place, not only because of meteors (流星) but also because of rays from the sun and other stars. The atmosphere again acts (67) our protective blanket on (68) . Light gets through, and this is essen- tial (69) plants to make the food which we (70) . Heat, (71) , makes our environments tolerable and some ultraviolet rays (紫外线 ) penetrate the (72) . Cosmic ( 宇宙的) rays of various kinds come (73) the air from outer space, but (74) quantities of radiation from the sun are screened off. As (75) as men leave the atmosphere they are (76) to this radiation; (77) their spacesuits or the walls of their spacecraft, if they are inside, (78) prevent a lot of radiation damage. Radiation is the greatest known danger to explorers in (79) . Doses of radiation are measured in (80) called "reins (霍姆)". We all 81 radiation here on earth from the sun, from cosmic rays and from radioactive minerals. The " (82) " dose of radiation that we receive each year is about 100 millirems; it (83) according to where you live, and this is a very rough estimate. Scientists have reason to think (84) a man can (85) up with far more radia- tion (86) this without being damaged; the figure of 60 rems has been agreed.

A. soon
B. well
C. much
D. possible

ERG的a波来自于( )

A. 神经节细胞
B. 无长突细胞
C. 光感受器
D. 双极细胞
E. 色素上皮

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