【hold on】 —

1. maintain one’s grip or footing:

• If a branch is near you, 【hold on】 until we can get a rope.

2. continue; last:

• If the weather holds on, the area should provide excellent hunting the next few days.

3. continue traveling in a certain direction:

• 【Hold on】 down the road until you come to the railway crossing.

4. wait on the telephone:

• I’m afraid the line is busy, would you like to 【hold on】 ?

5. continue in spite of difficulties; refuse to yield:

• Painting the house is tiring, but if you 【hold on】 , the results are worth the effort.

【keep on】 —

1. = 【hold on】 2:

• The rain kept on, and the wind increased. There would be no flying that day.

2. = 【hold on】 3:

• Turn left at the corner and 【keep on】 as far as the church. Keep right on to the end of the road.

3. = 【hold on】 5:

• Even if you fail the examination again, you must try to 【keep on】 until you pass.

4. talk at length about smth.:

• Don’t 【keep on】 so. I know you want the car but we can’t afford it.