phy 問題

If you use the same force on different direction, you can keep the object in a STILL POSITION. There is no relation between your two statements.
Your first statment is the work done against gravity, which means the energy is used in increasing the object's PE, your second statement should be explained by Newton's first law.
Newton's first lae tells that if the net force of an object is zero, then it will keep in constant velocity, please remind that v=0 is also constant velocity. If you use the same force on different direction against the gravity, by taking upward as positive, we have:
Force by gravity = -mg
Force by you = mg
Net force =Sum of all force = -mg + mg = 0
There will be no work done since F=0.
If and only if you use a force greater (smaller) than gravity, the object will move upward (downward) due to the non-zero net force, then there will by work done on/against (by) gravity.