keep sb at arm’s length;maintain a discreet distance; neither too familiar nor too distant
? 夜間我們緊跟著敵人，～。At night we followed the enemy at a discreet distance.
不即不離
be neither too close nor too distant;hang about sb while keeping a certain distance;keep at arm’s length
不即不離bù jí bù lí
即：接近。離：遠離、疏遠。對待他人的態(tài)度既不太接近，又不太疏遠。keep sb. at arm’s length, be neither familiar nor distant, be negatively friendly