put one's nose to the grindstone

address apply oneself attend to bend concentrate on dedicate oneself to devote oneself to exert oneself get serious give give oneself over to keep close to keep one's mind on knuckle down launch into occupy oneself with pitch in plunge into put one's hand to the plow set to swing into action take the bull by the horns throw turn

be lazy ignore relax

hammer away keep one's shoulder to the wheel peg away plug away struggle on wade through work hard