goodidea前面加什么

前面加冠词a，例如：

1、It would be a good idea to call before we leave.我们出发之前打个电话是个好主意。

2、It seemed like a good idea at the time， and then it all went horribly wrong.那在当时似乎是个好主意，但后来却铸成大错。

3、It seemed like a good idea at the time.当时这主意好像不错。