问题
单项选择题
缺铁性贫血最常见的原因()
A．铁吸收不良
B．慢性失血
C．铁摄入不足
D．红细胞本身缺陷
E．铁需要量增加
答案
参考答案：B
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缺铁性贫血最常见的原因()
A．铁吸收不良
B．慢性失血
C．铁摄入不足
D．红细胞本身缺陷
E．铁需要量增加
参考答案：B
| If you left your book on the table overnight, you would find the following morning that it was still exactly where you had left it, provided nobody had moved it. If a ball is made to roll on a very smooth surface, it will roll a long distance unless something stops it or changes its direction. This tendency of an object to remain at rest unless something moves it and to continue moving unless something stops it is known as the Law of Inertia. The following examples show the truth of this law. (a) Put a table-cloth on a table and arrange a pile of books on it. Hold one edge of the table-cloth and pull it quickly. The table-cloth will come off, leaving the pile of books undisturbed. (b) Place a small piece of cardboard on an open jar and place a coin on it directly over its mouth. Use one finger to flick the piece of cardboard away. You will notice that the coin drops into the jar. (c) Sitting in a car which starts suddenly, you feel you are jerked backwards. In fact, you are not jerked backwards. Your lower half, which is in contact with the cushion, is forced to move forward with the car, and the upper part of your body, which remained at rest, is left behind. |
In this passage, inertia means ______.
A．a situation in which no action is taken
B．a situation in which no progress is made
C．the feeling of someone not wanting to move or do anything
D．the force making an object stay at rest or continue moving