假設語氣

類型1 : 有可能發生的假設 (現在or未來式)
If Ray has time, he will make a video.
類型2 : 與現在事實相反 (過去式)
If Ray had time, he would make a video.
類型3 : 與過去事實相反(過去完成式)
If Ray had had time, he would have made a video.

類型1 : 

 類型2 :

 類型3 :