辨析：energy, strength, power 和 force

1.energy 为“精力，活力，能量”，指人或动物所积蓄的内在或释放的活力，也指物理学上的能量。

①.He is a man full of energy and he can do as much work as three men do.

②.Actually, it is energy that makes the earth go around.

2.strength 为“力气，力量”发挥的内在素质与体质，也可指物理学上的强度。

试比较：

①.All the passengers pushed the bus with all their strength, but it

   refused to move. （strength 指力气）

②.As the saying goes, "Unity is strength", let us work hard together to

   overcome the difficulties. （strength 指强度。）

3.power 为“力，力量，能力，权力”。它是力的总称，指各种力，如电力，动力或某事物的能力。

  它也可指人所具有的力量，能力，权力及势力等。当指人所具有的力气时，它与 strength 同义。

①.Electricity gives us power and makes machines work.

   (power 指电力)

②.As the saying goes, “Knowledge is power.”

   (power 指力量)

③.I'll do everything in my power to help that old lady.

   (power 指能力)

④.A football player needs power/strength to run with the ball.

   (power/strength 指体力)

4.force主要指外力，是推动人或物朝所要求的方向运动或能产生明显效应的力量。

①.He did it with a great force.

②.Matters of this kind should be solved in a peaceful way instead of

   by means of force.

When the new president comes into power, he carries out a series of workable and

favorable policies.

新任总统掌权后，实施了一系列可行而又有利的政策。

He has so much energy that he can work as hard as three men.(energy 指精力)

The successful carrying out of the work is due to his youth and energy.(energy 指活力)

The energy of the sun has been widely used now.(energy 指能量）