例如以下句子对比:
Please confirm attached new PO within 3 working days;
Kindly confirm receipt attached PO by return email in 3 working days.
Do sth. within +时间范围与 Do sth. by do sth. in + 时间范围表达可以互换吗?
“in +一段时间”和“within + 一段时间”表示“在多少时间之内”的意思时,前者只能与延续性动词连用,后者可以与延续性动词或者非延续性动词连用。