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问题 单项选择题

患者男性，55岁，平素体健，无自觉不适症状，半小时前突发心悸，胸闷，恐惧感急诊入院。平素心电图检查可见△波，入院查体：血压：86／60mmhg，心率>200次／分，心律绝对不齐，第一心音强弱不等。 该心律失常产生的机制（）

A.存在房室旁道

B.QT间期延长

C.洋地黄中毒

D.电解质紊乱

E.心肌严重缺氧

答案

参考答案：A

单项选择题

关于发卡银行应当遵守的信用卡业务，下列说法错误的是( )。

A．同—持卡人单笔透支发生额个人卡不得超过2万元(含等值外币)、单位卡不得超过 5万元(含等值外币)
B．同一账户月透支余额个人卡可以超过3万元(含等值外币)
C．从《银行卡业务管理办法》实施之日起新发生的180天(含180天，下同)以上的月均透支余额不得超过月均总透支余额的15%
D．准贷记卡的透支期限最长为60天
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单项选择题

The human nose is an underrated tool. Humans are often thought to be insensitive smellers compared with animals, (31) this is largely because, (32) animals, we stand upright. This means that our noses are (33) to perceiving those smells which float through the air, (34) the majority of smells which stick to surfaces. In fact, (35) , we are extremely sensitive to smells, (36) we do not generally realize it. Our noses are capable of (37) human smells even when these are (38) to far below one part in one million.
Strangely, some people find that they can smell one type of flower but not another, (39) others are sensitive to the smells of both flowers. This may be because some people do not have the genes necessary to generate (40) smell receptors in the nose. These receptors are the cells which sense smells and send (41) to the brain. However, it has been found that even people insensitive to a certain smell (42) can suddenly become sensitive to it when (43) to it often enough.
The explanation for insensitivity to smell seems to be that the brain finds it (44) to keep all smell receptors working all the time but can (45) new receptors if necessary. This may (46) explain why we are not usually sensitive to our own smells—we simply do not need to be. We are not (47) of the usual smell of our own house, but we (48) new smells when we visit someone else’s. The brain finds it best to keep smell receptors (49) for unfamiliar and emergency signals (50) the smell of smoke, which might indicate the danger of fire.

A．introduce

B．summon

C．trigger

D．create
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