如图为人体部分特异性免疫过程的示意图，a、b、c表示细胞。请据图回答下列问题。

(1)该特异性免疫属于       免疫，图中b细胞在人体内可以来自                   细胞。
(2)图中a、b、c、d能够识别抗原的是         。（填字母）
(3)若图中所示的抗原为酿脓链球菌，因其表面的抗原决定簇与人心脏瓣膜上的一种物质的表面结构十分相似，物质d向心脏瓣膜发起进攻，使人患上风湿性心脏病，这属于免疫失调中的             病。
(4)当抗原经过⑤⑥过程时，人体内产生d的主要特点是数量多、速度快，与合成与分泌d有关的细胞器有           、           、
           、           。
(5)研究发现，HIV病毒的增殖需要逆转录酶，从遗传物质分析，研究HIV疫苗比较困难的主要原因是                                                          。

We make traffic rules to keep order on the roads. These rules also help keep us  1  on the roads.

People have to  2  many traffic rules. In China, you must walk  3  the sidewalk or on the side of the road. Look carefully (仔细地) before you   4  the street.

If you are riding a bike, don't ride in the middle (中间) of the roads or run through (通过) the road when the traffic light is   5 . When you ride a bike   6  a friend, don't look around and talk.

If you drive, you must slow down at the traffic lights. You must always   7  a seat belt安全带). Without (没有) belts,   8  the driver and the other people in the car may hurt themselves when the car stops suddenly (突然地).

When you take a bus, you must be  9 . Get on or get off a bus only when it comes to a  10  When it’s full (满的), you shouldn't get on it or you may fall down.

1.                A．happy          B．safe            C．dangerous D．quiet

 

2.                A．miss           B．show           C．obey D．take

 

3.                A．on            B．in             C．at   D．across

 

4.                A．walk           B．cross           C．walk cross D．across

 

5.                A．brown          B．black           C．green    D．red

 

6.                A．with           B．and            C．about    D．from

 

7.                A．bring          B．dress           C．wear     D．take

 

8.                A．every          B．both           C．each D．between

 

9.                A．glad           B．interesting      C．careful   D．wonderful

 

10.               A．school         B．sign           C．corner    D．stop