一项工作，A、B两人合作完成其
需要6天，A完成
与B完成
所用时间相同，那么，A、B单独完成工作各需（）天。
A．18，14
B．18，16
C．12，16
D．18，12
参考答案：D
解析：
[本题考点] 这是一道“工程”类型的试题。 [解题思路] 设A单独完成需要a天，B单独完成需要b天，由题意可得：
，解得a=18，b=12，故选D。
| 阅读理解。 | |
| The Blacks and the Whites are good neighbors. They know each other well. Sometimes they have dinner together. Yesterday,Mrs Black invited the Whites to have dinner again because it was her birthday. In the afternoon，she came home from work early. On the way home,she went to the market and bought a lot of food. First she bought some beef because Mr Black liked it best. And she knew that Mr White liked chicken and Mrs White’s favorite food was fish. So she bought some chicken and fish. She also bought some vegetables and fruit. She wanted to get everything ready for the dinner. When Mr Black came back home,Mrs Black was busy cooking. “Happy birthday!" Mr Black said and brought her a bunch of flowers. “Oh，thanks. What beautiful flowers!Would you please put them in the sitting room? I’m busy now.” "OK,”said Mr Black. “And I can help you put the candles on the birthday cake. ” "A birthday cake?”Mrs Black said,“I forgot to buy it. ” "Never mind. I’ll buy it now. I’ll be back in a few minutes.”Mr Black said while he was running towards the door. Just then,the doorbell rang. They were the Whites. In their hands there was a big birthday cake. | |
| 1. The Black family and the White family ___________. | |
| A. live next door to each other B. live in different cities C. live in the same house D. are going to the park | |
| 2. It was ___________birthday yesterday. | |
| A. Mr White’s B. Mrs White’s C. Mr Black’s D. Mrs Black’s | |
| 3. Mrs Black bought ___________but she forgot to buy___________. | |
| A. a lot of food；fruit B. everything；vegetables C. a lot of food；a birthday cake D. some flowers； meat | |
| 4. What present did the Whites bring? | |
| A. A bunch of flowers. B. A big birthday cake. C. A box of fruit. D. A lovely dog. | |
| 5. Why did Mrs Black come home early? | |
| A. Because she had to get everything ready for the dinner. B. Because Mrs White told her to do so. C. Because she wanted to go shopping with Mrs White. D. Because she was ill. |