问题
选择题
已知i为虚数单位，a为实数，复数z=（a﹣2i）（1+i）在复平面内对应的点为M，则“a=1”是“点M在第四象限”的 [ ]
A．充分而不必要条件
B．必要而不充分条件
C．充要条件
D．既不充分也不必要条件
答案
答案：A
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已知i为虚数单位，a为实数，复数z=（a﹣2i）（1+i）在复平面内对应的点为M，则“a=1”是“点M在第四象限”的 [ ]
A．充分而不必要条件
B．必要而不充分条件
C．充要条件
D．既不充分也不必要条件
答案：A
| 完形填空。 | ||||
| Two brothers worked together on a farm. One was married and had a large 1 . The other had no wife yet. Although they lived in different houses, they shared everything they got from their farm. One day, the single brother said to himself, "It's not 2 that we share all the rice. I'm 3 and I need less than my brother." So, every night he took a bag of rice from his store-room and 4 across the field 5 their houses, putting it into his brother's store-room. At the same time, the married brother thought, "It's not fair to share all the rice. I'm married and I have my wife and children to 6 me when I am 7 . However, my brother has no one to take care of his 8 " So, each night he also took a bag of rice and put it into his brother's store-room. Several months passed by. They found 9 strange that their rice never became less. Then, one dark night the two brothers ran into each other. Slowly they began to understand what was happening. Their bags fell onto the ground and tears 10 their eyes at once. | ||||
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