Seize the chance,otherwise you will regret it.
抓住機會(huì ),要不然你會(huì )后悔的。
I was ill that day,otherwise I would have taken part in the sports meet.
那天我病了,否則我會(huì )去參加運動(dòng)會(huì )的。
We didn’t know you were in trouble at that time,otherwise we would have given you a hand.
我們當時(shí)不知道你遇到了困難,要不然我們會(huì )幫助你的。