整个补体激活过程大致可分为三个阶段，其顺序为
A．激活阶段→识别阶段→膜攻击阶段
B．识别阶段→膜攻击阶段→激活阶段
C．激活阶段→膜攻击阶段→识别阶段
D．识别阶段→激活阶段→膜攻击阶段
E．膜攻击阶段→膜攻击阶段→识别阶段
参考答案：D
解析： 补体活化过程表现为一系列丝氨酸蛋白酶的级联酶解反应。识别后，通过三条激活途径，形成膜攻击复合物，最终导致细胞崩解。
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| Mr. Smith 1 in a post office three years ago. When he was sixty, he retired. Now he and his wife stay at home and his children work in 2 city. The old man does all housework and he has nothing to do at home. He likes neither reading nor 3 games. At first he didn't know how to 4 the free time. Mr. Hunt 5 was two years older than him asked to go fishing with him. "It's a good sport," said Mr. Hunt. "I'm sure you'll soon be 6 in it." "That's easy. Go fishing with me tomorrow morning and I'll 7 you." Mr. Smith decided 8 his luck. The following day the two old friends came to a river and began to fish. Suddenly Mr. Smith said, "I say, 9 do those little red things cost?" "You mean the floats (浮子)? Oh, they're cheap. What made you ask me such a 10 ?" "I owe (欠) you for one. Mine has just sunk (下沉)." | ||
| ( )1. A. work ( )2. A. other ( )3. A. playing ( )4. A. spend ( )5. A. who ( )6. A. interesting ( )7. A. discover ( )8. A. trying ( )9. A. how many ( )10. A. problem | B. worked B. the other B. play B. take B. which B. interested B. teach B. to try B. how far B. answer | C. works C. another C. plays C. cost C. what C. interest C. follow C. tried C. how much C. question |