问题 单项选择题

伤寒杆菌的主要致病因素()

A.外毒素

B.伤寒内毒素

C.细菌的侵袭力

D.H抗原

E.肠毒素

答案

参考答案:B

解析:这是一道理解、记忆题。考核学生对伤寒致病因素的认识。预测错误率不高。常见错误:①选答"C","细菌的侵袭力"与伤寒的发病有关,但不是主要致病因素;②选答"E""肠毒素"不是伤寒的致病因素,伤寒杆菌并不产生肠毒素及外毒素。应复习伤寒杆菌的致病因素。要点伤寒杆菌不产生外毒素,菌体裂解时释放的内毒素是伤寒杆菌的主要致病因素。

单项选择题
单项选择题

When Dave was eighteen, he bought a secondhand car for 200 so that he could travel to and from work more (1) than by bus. It worked quite well for a few years, but then it got so old, and it was costing him (2) much in repairs that he decided that he had better (3) it.

He asked among his friends to see if anyone was particularly (4) to buy a cheap car, but they all knew that it was falling to pieces, so (5) of them had any desire to buy it. Dave’s friend Sam saw that he was (6) when they met one evening, and said, "What’s (7) , Dave"

Dave told him, and Sam answered, "Well, what about advertising it in the paper You may (8) more for it that way than the cost of the advertisement!" Thinking that Sam’s (9) was sensible, he put an advertisement in an evening paper, which read "For sale: small car, (10) very little petrol, only two owners. Bargain at 50. " For two days after the advertisement first appeared, there was no (11) . But then on Saturday evening he had an enquiry. A man rang up and said he would like to (12) him about the car. "All right, " Dave said, feeling happy. He asked the man whether ten o’clock the next morning would be (13) or not. "Fine, " the man said, "and I’ll (14) my wife. We intend to go for a ride in it to (15) it. "

The next morning, at a quarter to ten, Dave parked the car in the square outside his front door, (16) to wait there for the people who had (17) his advertisement. Even Dave had to (18) that the car really looked like a wreck. Then, soon after he had got the car as clean (19) it could be, a police car stopped just behind him and a policeman got out. He looked at Dave’s car and then said, "Have you reported this (20) to us yet, sir\

18().

A.forget 

B.show 

C.disagree 

D.admit