7的英文怎么写

　　It's difficult for them to get here much before seven.

　　他们很难在7点以前早早地来到这里。

　　Two plus five is seven.

　　二加五等于七。

　　You should receive a reply within seven days.

　　你会在七天之内收到答复。

　　The ticket gives you unlimited travel for seven days.

　　凭本车票在七日内可自由乘车不受限制。

　　Seven from ten leaves three.

　　10减7得3。