问题 选择题

下图是X、Y、Z、W四种溶液的近似pH。下列判断不正确的是

A.X一定显酸性

B.Y一定是水

C.Z一定显碱性

D.W的碱性一定比Z强

答案

答案:B

题目分析:溶液的PH小于7的呈酸性,大于7的呈碱性;等于7的呈中性。X的PH=2,一定呈酸性;Y的PH=7,溶液呈中性,但不一定是水;Z的PH=10,一定呈碱性;W的PH=13,碱性强于Z。选B。

点评:PH大于7的溶液是碱性的,小于7的是酸性的,等于7的是中性的。

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\

7()

A.on 

B.up 

C.it 

D.that