在直角坐标系xOy中，以原点O为极点，x轴正半轴为极轴建立极坐标系．若曲线C的极坐标方程为ρcos²θ﹣4sinθ=0，P点的极坐标为 $\left(3,\frac{\pi }{2}\right)$ ，在平面直角坐标系中，直线l经过点P，斜率为 $\sqrt{3}$

（Ⅰ）写出曲线C的直角坐标方程和直线l的参数方程；

（Ⅱ）设直线l与曲线C相交于A，B两点，求 $\frac{1}{\left|PA\right|}+\frac{1}{\left|PB\right|}$ 的值．

中医常通过“切脉”诊断疾病，选择的血管是静脉。

铁有三种常见的氧化物：FeO、Fe₂O₃、Fe₃O₄．现有某铁的氧化物样品，已知其中铁元素与氧元素的质量比是21：8，关于该样品的说法正确的是（　　）

词汇运用 用所给词的适当形式填空
⑴Thank you for____ on them on the plane. (operate)
⑵I thought of my good friend when I read your____ (advertise)
⑶We should help all children to get an____   at school. (educate)
⑷His father died because of____ (ill).
⑸The old man is ____  to the policeman. (grate)
⑹I was made____ (read) the text once more by Miss Chen.
⑺I think I should Share his ____ when he is sad. (happy)
⑻He says that he wants to be a____ (fly) doctor when he leaves school.
⑼I don't know what made him laugh so____ (excite)?
⑽My watch doesn't work. It needs to____  (repair).
⑾Coffee ____  by most Chinese people. (not drink)
⑿He spend his spare time____  watching TV. (most)
⒀The car was one of the ____ . (run)
⒁ORBIS is one of the____  in the world. (charity)
⒂Many people in poor area don't have enough money for____  treatment. (medicine)