keep the enemy guessing

тримати противника в напрузі; спантеличувати; змушувати противника ‘ламати голову’ (The task force had done what it could to keep them guessing. - Bowden, Mark. Black Hawk Down - p. 21)

keep the enemy alerted

keep the enemy down

keep the enemy troops alerted unnecessarily

keep the enemy on the run

keep the enemy in check

overwhelm an enemy / overwhelm the enemy

keep the powder dry

keep-out altitude

keep the spacing

keep a close watch on foreigners

keep a tank in serviceable condition

keep road clear for traffic

keep the place clean

keep clear of the aircraft

keep abreast of the (battle) situation

keep at general quarters

keep on the run

keep the map up to date

keep pace with the armor

keep under fire

keep advised of the situation

keep in touch with the situation

keep abreast of the situation