问题
单项选择题 A1/A2型题
男，1岁。咳嗽1天，发热3小时，T39.3℃，就诊过程中突然双眼上翻，肢体强直，持续1分钟。查体：咽红，心肺腹及神经系统无异常，半年前也有相同病史。最可能的诊断是（）
A.癫痫
B.低钙惊厥
C.中毒性脑病
D.化脓性脑膜炎
E.高热惊厥
答案
参考答案：E
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男，1岁。咳嗽1天，发热3小时，T39.3℃，就诊过程中突然双眼上翻，肢体强直，持续1分钟。查体：咽红，心肺腹及神经系统无异常，半年前也有相同病史。最可能的诊断是（）
A.癫痫
B.低钙惊厥
C.中毒性脑病
D.化脓性脑膜炎
E.高热惊厥
参考答案：E
| The most popular organic gem is the pearl. A pearl is the response of a marine mollusk to the presence of an irritating impurity accidentally introduced into its body; a cultured pearl is the result of the intentional insertion of a mother-of-pearl bead into a live mollusk. Whether introduced accidentally or intentionally, the pearl-making process is the same: the mollusk coats the irritant with a substance called nacre. Nacre is composed chiefly of calcium carbonate. Because very few natural pearls are now on the market, most pearls used in free jewelry are cultured. These include "Biwa" pearls and most other freshwater pearls. Cultured pearls are not easily distinguished from natural pearls except by an expert. |
What is the chief component of nacre
A．Sand.
B．Bead.
C．Calcium carbonate.
D．Biwa.