A light went on at seven every evening.

　　一盞燈每晚七點(diǎn)鐘亮。

　　The journey took approximately seven hours.

　　旅程大約花了七個(gè)小時(shí)。

　　You should receive a reply within seven days.

　　你會在七天之內(nèi)收到答復(fù)。