ipad前冠词用a还是an

前用冠词an，例如：

1、She also has an iPad and a smartphone.她还有一台平板电脑和一部智能手机。

2、The opposite of a wallet is a smartphone or an iPad.智能手机或iPad正在取代钱包。

3、"You'll want an iPad just so you can wear this" is the slogan for one of the new lab coats designed with large pockets to accommodate tablet computers.“穿上它，你就会想要一部iPad”是其中一款新实验服的标语，这些新实验服设计有可以装平板电脑的大口袋。