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问题 填空题

已知一个正比例函数的图象经过点（-1，3），则这个正比例函数的表达式是______．

答案

设正比例函数的表达式是y=kx（k≠0），

∵正比例函数的图象经过点（-1，3），

∴3=-k，即k=-3．

则这个正比例函数的表达式是y=-3x．

单项选择题

A client with a history of heart failure is examined in the outpatient department to investigate the recent onset of peripheral edema and increased shortness of breath. Physical　findings include bilateral crackles, a third heart sound (S3), distended neck veins, elevated blood pressure, and pitting edema of the ankles. The nurse documents the severity of pitting edema as +1. What is the best description of this type of edema（）

A. Barely detectable depression when the thumb is released from the swollen area; normal foot and leg contours.

B. Detectable depression of less than 5 mm when the thumb is released from the swollen area; normal foot and leg contours.

C. A 5-to 10-mm depression when the thumb is released from the swollen area; foot and leg swelling.

D. A depression of more than 1 cm when the thumb is released from the swollen area; severe foot and leg swelling.
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选择题

人的呼吸器官是肺，植物的呼吸部位是（　　）

A．只有幼小的果实

B．只有生长旺盛的叶片

C．只有根尖的根毛

D．植物体内任何的活细胞
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