If you do not come, I shall presume that the deal is off.如果你不来, 我就当这笔交易告吹了。

I presume you're here on business.我想你来这儿是出差的。

I presume so我认为如此

Had he been home all week?—I presume so.他整个礼拜都待在家吗？——我想是的。